South Korea
Opensignal is the independent global standard for analyzing consumers' connectivity experiences. Our industry reports are the definitive guide to understanding what happens when people use their mobile and broadband connections in their daily life.
South Korea
Opensignal is the independent global standard for analyzing consumers' connectivity experiences. Our industry reports are the definitive guide to understanding what happens when people use their mobile and broadband connections in their daily life.
Key Findings
SK Telecom wins the Best Network award
SK Telecom dominates the award table, securing 9 sole wins and 3 joint wins. It turns previous joint wins into outright wins for Upload Speed Experience, 5G Video Experience and 5G Upload Speed. SK Telecom also earns the title of Best Network, which recognizes operators providing outstanding overall experiences nationally in key Opensignal metrics.
LG U+ is the 5G Availability leader in South Korea
LG U+ wins 5G Availability with a score of 90.3%, which reflects the proportion of time Opensignal users with a 5G device and a 5G subscription have a 5G connection, whether or not it was actively used.
KT users enjoy the fastest 5G Download Speeds
KT claims the 5G Download Speed award, ahead of SK Telecom by 20 Mbps and LG U+ by 34.5 Mbps. This represents a change from the previous report, in which KT shared the top spot with LG U+.
SK Telecom remains the outright winner in Consistent Quality and Reliability Experience
SK Telecom delivers the highest levels of consistent quality and reliability among operators. It leads Consistent Quality by 7 percentage points over LG U+ and 12.3 points over KT, while also holding significant leads of 29 and 60 points in Reliability Experience, respectively.
Mobile Experience Awards
Market Overview
SK Telecom continues to lead the awards landscape in South Korea, securing 9 awards outright and sharing 3 additional wins. This performance demonstrates the operator's ability to excel across a wide range of user experience metrics, including speed, consistency, and reliability. Meanwhile, LG U+ and KT each hold three awards, LG U+ triumphs for 5G Availability, while KT for 5G Download Speed.
SK Telecom recently announced a major restructuring of its business, creating two focused divisions: one for its core mobile network operations (MNO) and another dedicated to its AI business. The MNO division will prioritize strengthening the competitiveness of its network and products, while the AI division will concentrate on delivering near-term commercial outcomes. As part of this strategy, SK Telecom has committed KRW 5 trillion (USD 3.6 billion) in AI investment over the next five years.
In this report, Opensignal introduces a revised 5G Availability metric, which defines the proportion of time Opensignal users with a 5G device and a 5G subscription have a 5G connection, whether or not it was actively used. Previously, the metric measured the proportion of time Opensignal users with a 5G device and a 5G subscription utilized an active 5G connection — which is now reflected by Time on 5G. Additionally, our Availability metric has been renamed to Time on Network to align with methodological updates in other metrics.
In this report we examine the mobile network experience of the three main mobile network operators in South Korea — KT, LG U+ and SK Telecom — over a period of 90 days starting on August 1, 2025, and ending on October 29, 2025, to see how they fared.
Overall Experience
National Analysis
SK Telecom wins the Video Experience award outright with a score of 76.6 points on a 100-point scale and a lead of four points over second-placed KT's 73 points.
All operators place in the Very Good (68-78) category. This means that our users are, on average, able to stream video at 1080p or better with satisfactory loading times and little stalling.
Video Experience scores account for adaptive bitrate streaming (ABR), a technology that allows Opensignal to accurately represent users' real video experience including video streams up to 4K quality.
Definitions
Opensignal’s Video Experience quantifies the quality of video streamed to mobile devices by measuring real-world video streams over an operator's networks. The metric is based on an International Telecommunication Union (ITU) approach, built upon detailed studies which have derived a relationship between technical parameters, including picture quality, video loading time and stall rate, with the perceived video experience as reported by real people. To calculate video experience, we are directly measuring video streams from end-user devices and using this ITU approach to quantify the overall video experience for each operator on a scale from 0 to 100. The videos tested include a mixture of resolutions — including Full HD (FHD) and 4K / Ultra HD (UHD) — and are streamed directly from the world’s largest video content providers.
In addition to Video Experience, we report on the following metrics related to video experience:
- 5G Video Experience: The average Video Experience of Opensignal users when they were connected to an operator’s 5G network.
- Video Experience – 5G Users: The average Video Experience of Opensignal users with a 5G device and a 5G subscription across an operator's networks. It factors in 2G, 3G, 4G and 5G video experience along with the availability of each technology.
- 4G Video Experience: The average Video Experience of Opensignal users on an operator's 4G network.
- 3G Video Experience: The average Video Experience of Opensignal users on an operator’s 3G network.
National Analysis
SK Telecom and LG U+ win the Games Experience award jointly with statistically tied scores of 89.7-89.8 points on a 100-point scale and a lead of around two points over third-placed KT's 88.1 points.
All South Korean operators rate as Excellent (85 or above).
An Excellent (85 or above) rating means that the vast majority of users deem this network experience acceptable. Nearly all users feel like they have control over the game and they receive immediate feedback on their actions. There is not a noticeable delay in almost all cases.
Definitions
Opensignal’s Games Experience measures how mobile users experience real-time multiplayer mobile gaming on an operator’s network. Measured on a scale of 0-100, it analyzes how our users’ multiplayer mobile gaming experience is affected by mobile network conditions including latency, packet loss and jitter.
Games Experience quantifies the experience when playing real-time multiplayer mobile games on mobile devices connected to servers located around the world. The approach is built on several years of research quantifying the relationship between technical network parameters and the gaming experience as reported by real mobile users. These parameters include latency (round trip time), jitter (variability of latency) and packet loss (the proportion of data packets that never reach their destination). Additionally, it considers multiple genres of multiplayer mobile games to measure the average sensitivity to network conditions. The games tested include some of the most popular real-time multiplayer mobile games (such as Fortnite, Pro Evolution Soccer and Arena of Valor) played around the world.
Calculating Games Experience starts with measuring the end-to-end experience from users’ devices to internet end-points that host real games. The score is then measured on a scale from 0 to 100.
In addition to Games Experience, we report on the following metrics related to games experience:
- 5G Games Experience: The average Games Experience of Opensignal users when they were connected to an operator’s 5G network.
- Games Experience – 5G Users: The average Games Experience of Opensignal users with a 5G device and a 5G subscription across an operator's networks. It factors in 2G, 3G, 4G and 5G games experience along with the availability of each technology.
- 4G Games Experience: The average Games Experience of Opensignal users on an operator's 4G network.
- 3G Games Experience: The average Games Experience of Opensignal users on an operator's 3G (e.g. UMTS/HSPA or CDMA 1X EV-DO) network.
National Analysis
SK Telecom once again wins the Download Speed Experience award outright with a score of 189.3Mbps and a lead of 35Mbps over second-placed KT's 154.3Mbps.
All South Korean operators have observed increases in their scores. SK Telecom's score increased by 31 Mbps, KT's by 21 Mbps, and LG U+'s by 19 Mbps.
Definitions
Measured in Mbps, Download Speed Experience represents the typical everyday speeds a user experiences across an operator’s mobile data networks.
In addition to Download Speed Experience, we report on the following metrics related to download speeds:
- 5G Download Speed: The average download speed observed by Opensignal users with active 5G connections.
- Download Speed Experience – 5G Users: The average download speeds experienced by Opensignal users with a 5G device and a 5G subscription across an operator’s networks. It factors in 2G, 3G, 4G, and 5G download speeds along with the availability of each technology.
- 4G Download Speed: The average downlink speed observed by Opensignal users when they were connected to 4G.
- 3G Download Speed: The average downlink speed observed by Opensignal users when they were connected to 3G (e.g. UMTS/HSPA or CDMA 1X EV-DO).
National Analysis
In the previous report, the award was won by SK Telecom and LG U+ jointly. SK Telecom breaks out of the statistical tie and wins the Upload Speed Experience award outright with a score of 26.6Mbps and a lead of 1Mbps over second-placed LG U+'s 25.3Mbps. KT comes third with a score of 18.9Mbps.
SK Telecom's score increased by 3 Mbps, while LG U+ rose by 2 Mbps and KT by 1 Mbps.
Definitions
Upload Speed Experience measures the average upload speeds for each operator observed by our users across their mobile data networks. Typically upload speeds are slower than download speeds, as current mobile broadband technologies focus resources on providing the best possible download speed for users consuming content on their devices. As mobile internet trends move away from downloading content to creating content and supporting real-time communications services, upload speeds are becoming more vital and new technologies are emerging that boost upstream capacity.
In addition to Upload Speed Experience, we report on five supporting metrics related to upload speeds:
- 5G Upload Speed: The average upload speed observed by Opensignal users with active 5G connections.
- Upload Speed Experience – 5G Users: The average upload speeds experienced by Opensignal users with a 5G device and a 5G subscription across an operator’s networks. It factors in 2G, 3G, 4G, and 5G upload speeds along with the availability of each technology.
- 4G Upload Speed: The average uplink speed observed by Opensignal users when they were connected to 4G.
- 3G Upload Speed: The average uplink speed observed by Opensignal users when they were connected to 3G (e.g. UMTS/HSPA or CDMA 1X EV-DO).
5G Experience
National Analysis
SK Telecom wins the 5G Video Experience award outright with a score of 78.4 points on a 100-point scale and a lead of around two points over second-placed LG U+'s and KT's statistically tied scores of 76.7-77 points.
SK Telecom places in the Excellent (78 or above) category, while LG U+ and KT place one category lower, in Very Good (68-78).
An Excellent (78 or above) rating means that our users are, on average, able to stream video at 1080p or better with fast loading times and no stalling. A Very Good (68-78) rating means that our users are, on average, able to stream video at 1080p or better with satisfactory loading times and little stalling.
5G Video Experience scores account for adaptive bitrate streaming (ABR), a technology that allows Opensignal to accurately represent users' real video experience including video streams up to 4K quality.
Definitions
5G Video Experience quantifies the quality of mobile video experienced by Opensignal users on real-world video streams when they were connected to 5G. The metric is based on an International Telecommunication Union (ITU) approach, built upon detailed studies which have derived a relationship between technical parameters, including picture quality, video loading time and stall rate, with the perceived video experience as reported by real people. To calculate 5G Video Experience, we are directly measuring video streams from end-user devices and using this ITU approach to quantify the video experience observed by our users on each operator’s 5G network on a scale from 0 to 100. The videos tested include a mixture of resolutions — including Full HD (FHD) and 4K / Ultra HD (UHD) — and are streamed directly from the world’s largest video content providers.
National Analysis
In the previous report, the award was won by SK Telecom, LG U+ and KT jointly. This time, LG U+ slips off the winners' podium, as SK Telecom and KT win the 5G Games Experience award jointly with statistically tied scores of 93.8-93.9 points on a 100-point scale.
All operators place in the Excellent (85 or above) category.
An Excellent (85 or above) rating means that the vast majority of users deem this network experience acceptable. Nearly all users feel like they have control over the game and they receive immediate feedback on their actions. There is not a noticeable delay in almost all cases.
Definitions
5G Games Experience measures how mobile users experience real-time multiplayer mobile gaming on an operator's 5G network. It analyzes how our users’ multiplayer mobile gaming experience was affected by mobile network conditions including latency, packet loss and jitter. 5G Games Experience for each operator is calculated on a scale from 0 to 100.
5G Games Experience quantifies the experience when playing real-time multiplayer mobile games on mobile devices connected to servers located around the world. The approach is built on several years of research quantifying the relationship between technical network parameters and the gaming experience as reported by real mobile users. These parameters include latency (round trip time), jitter (variability of latency) and packet loss (the proportion of data packets that never reach their destination). Additionally, it considers multiple genres of multiplayer mobile games to measure the average sensitivity to network conditions. The games tested include some of the most popular real-time multiplayer mobile games (such as Fortnite, Pro Evolution Soccer and Arena of Valor) played around the world. Calculating 5G Games Experience starts with measuring the end-to-end experience from users’ devices to internet end-points that host real games.
National Analysis
In the previous report, the award was won by LG U+ and KT jointly. KT takes home the 5G Download Speed award outright with a score of 486.2Mbps and a lead of 20Mbps over second-placed SK Telecom's 466Mbps.
SK Telecom's score has increased by 34Mbps while KT's score has increased by 26Mbps. LG U+'s score hasn't changed a significant amount since the previous report.
Definitions
5G Download Speed shows the average download speed experienced by Opensignal users across an operator’s 5G network. 5G Download Speed for each operator is calculated in Mbps (Megabits per second).
National Analysis
SK Telecom wins the 5G Upload Speed award outright with a score of 57.4Mbps and a lead of 3Mbps over second-placed LG U+'s 54.5Mbps. KT comes third with a score of 47.3Mbps.
SK Telecom's score increased by 3 Mbps, LG U+'s by 2 Mbps, while KT's score fell by 4 Mbps.
Definitions
5G Upload Speed measures the average upload speeds experienced by Opensignal users across an operator’s 5G network. 5G Upload Speed for each operator is calculated in Mbps (Megabits per second).
Coverage
National Analysis
SK Telecom retains the Coverage Experience award outright with a score of 9.4 points on a 10-point scale and a lead of less than one point over second-placed KT's 9.1 points. LG U+ comes third with a score of 8.6 points.
These scores indicate that SK Telecom has the widest geographic coverage footprint in populated areas among all mobile operators in South Korea.
Definitions
The Opensignal Coverage Experience metric measures the extent of mobile networks in the places people live, work and travel. The metric represents the experience users receive as they travel around areas where they would reasonably expect to find coverage.
Traditional coverage metrics typically estimate either a percentage of land area covered, or a percentage of population covered; often neither will be an accurate measurement of the true user expectation and experience. In many markets there are areas where neither population density nor geographic area reflect the importance of coverage to users. For example, in a large mountain range most users will not expect coverage in the wilderness, but poor coverage in the relatively small area of a ski resort is critical for the enjoyment of a holiday. Estimates based purely on population give undue significance to coverage in the most densely populated areas.
Coverage Experience measures geographic coverage of populated areas and therefore more accurately reflects the coverage expectations and experience of typical users. It can give a result that is somewhat different to traditional estimates based on either geographic or population measures. The metric uses a scale from 0 to 10.
National Analysis
SK Telecom wins the 5G Coverage Experience award outright with a score of 7.3 points on a 10-point scale and a lead of less than one point over second-placed KT's seven points. LG U+ comes third with a score of 5.5 points.
Definitions
The Opensignal Coverage Experience metric measures the extent of mobile networks in the places people live, work and travel. The metric represents the experience users receive as they travel around areas where they would reasonably expect to find coverage.
Traditional coverage metrics typically estimate either a percentage of land area covered, or a percentage of population covered; often neither will be an accurate measurement of the true user expectation and experience. In many markets there are areas where neither population density nor geographic area reflect the importance of coverage to users. For example, in a large mountain range most users will not expect coverage in the wilderness, but poor coverage in the relatively small area of a ski resort is critical for the enjoyment of a holiday. Estimates based purely on population give undue significance to coverage in the most densely populated areas.
Coverage Experience measures geographic coverage of populated areas and therefore more accurately reflects the coverage expectations and experience of typical users. It can give a result that is somewhat different to traditional estimates based on either geographic or population measures. The metric uses a scale from 0 to 10.
5G Coverage Experience shows the proportion of places Opensignal users with a 5G device and a 5G subscription had an active 5G connection.
National Analysis
All three South Korean operators remain locked in a statistical tie for Time on Network with identical scores of 99.9%. This figure represents the proportion of time Opensignal users spend connected to a 5G, 4G, or 3G mobile signal.
Definitions
Our time on network and availability metrics are not measures of a network’s geographical extent. They won’t tell you whether you are likely to get a signal if you plan to visit a remote rural or nearly uninhabited region. Instead, they measure what proportion of time people have a network connection, in the places they most commonly frequent — something often missed by traditional coverage metrics. Looking at when users have a connection rather than where, provides us with a more precise reflection of the true user experience.
We also keep track of the instances that leave mobile users most frustrated: when there is no signal to connect to at all. The most common dead zones users struggle with occur indoors. As most of our time on network data is collected indoors (as that’s where users spend most of their time), we’re particularly astute at detecting areas of zero signal.
Our time on network and availability metrics take a user-centric, time-based approach that complements the user-centric and geographical-based methodology used by our reach metrics.
Time on Network shows the proportion of time all Opensignal users on an operator’s network had either a 3G, 4G or 5G connection.
National Analysis
LG U+ wins 5G Availability with a score of 90.3%, which reflects the proportion of time Opensignal users with a 5G device and a 5G subscription have a 5G connection, whether or not it was actively used.
Definitions
Our time on network and availability metrics are not measures of a network’s geographical extent. They won’t tell you whether you are likely to get a signal if you plan to visit a remote rural or nearly uninhabited region. Instead, they measure what proportion of time people have a network connection, in the places they most commonly frequent — something often missed by traditional coverage metrics. Looking at when users have a connection rather than where, provides us with a more precise reflection of the true user experience.
We also keep track of the instances that leave mobile users most frustrated: when there is no signal to connect to at all. The most common dead zones users struggle with occur indoors. As most of our time on network data is collected indoors (as that’s where users spend most of their time), we’re particularly astute at detecting areas of zero signal.
Our time on network and availability metrics take a user-centric, time-based approach that complements the user-centric and geographical-based methodology used by our reach metrics.
5G Availability shows the proportion of time Opensignal users with a 5G device and a 5G subscription had a 5G connection, whether or not it was used.
Consistency
National Analysis
SK Telecom wins the Consistent Quality award outright with a score of 90.7% and a lead of eight percentage points over second-placed LG U+'s 83%. KT comes third with a score of 78.4%.
KT's score increased by six percentage points, SK Telecom's rose by less than one point, while LG U+'s score fell by one percentage point.
This metric measures if the network is sufficient to support common mobile application requirements at a level that is 'good enough' for users to maintain (or complete) various typical demanding tasks on their devices. It assesses a number of experience indicators such as download speed, upload speed, latency, jitter, packet loss, and time to first byte.
Definitions
Consistent Quality measures if the network is sufficient to support common mobile application requirements at a level that is ‘good enough’ for users to maintain (or complete) various typical tasks on their devices.
We combine different experience indicators such as download throughput, upload throughput, latency, jitter, packet discard, and time to first byte to calculate Consistent Quality. These components are evaluated against thresholds recommended by various more demanding common applications used for a range of common tasks.
To calculate the metric value, the proportion of tests that pass the requirements of Consistent Quality is multiplied by the test success ratio, which is the proportion of completed tests to all tests conducted. Tests that pass indicate that activities such as video calling, uploading an image to social media, or using smart home applications will be possible without noticeable lag or slowdown.
National Analysis
SK Telecom wins the Reliability Experience award outright with a score of 971 points on a 100-1000 point scale and a lead of 29 points over second-placed LG U+'s 942 points. KT comes third with a score of 911 points.
KT's score increased by 49 points, SK Telecom's by 14 points, and LG U+'s by eight points.
Opensignal's Reliability Experience measures the ability of our users to connect to and successfully complete basic tasks on operators' networks. It consists of the following components:
a) Signal Availability — the proportion of time Opensignal users can successfully receive a mobile network signal,
b) Data Connectivity — the proportion of time when the network is available and the device can connect to the internet,
c) Task Completion — whether tasks initiated by the user's device are completed,
d) Sufficiency — the probability that basic tasks will be executed sufficiently well for the user.
Definitions
Opensignal’s Reliability Experience measures the ability of Opensignal users to connect to and successfully complete (basic) tasks on communication service providers’ (CSP) networks. It analyzes how much Opensignal users’ experience is affected by the radio access and core network, along with issues that prevent them from connecting to the internet even if they have a connection to their CSP’s network. It also factors in users’ ability to successfully use lower performance applications including SD video, over-the-top voice calls and web browsing.
Related Analysis
Our Methodology
Collecting billions of individual measurements daily from over 100 million devices globally, Opensignal independently analyzes mobile and broadband user experience on every major network operator around the globe.
About Opensignal
Opensignal is the leading global provider of independent insights into consumers' connectivity experiences and choice of carrier. Our proprietary insights into mobile and broadband networks give operators the solutions they need to profitably compete and win, from executive level scorecards and public validation to pin-point level engineering analytics and consumer decision dynamics.
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Confidence Intervals
For every metric we calculate statistical confidence intervals indicated on our graphs. When confidence intervals overlap, our measured results are too close to declare a winner. In those cases, we show a statistical draw. For this reason, some metrics have multiple operator winners.
In our bar graphs we represent confidence intervals as boundaries on either sides of graph bars.
In our supporting-metric charts we show confidence intervals as +/- numerical values.
Why confidence intervals are vital in analyzing mobile network experience