It may have taken the arrival of 5G, but some of Asia's biggest operators are finally getting around to shutting off 2G.

South Korea's SK Telecom this week began turning off its 23-year-old network, which still supports around 380,000 customers.

After a lawsuit over the closure, the regulator requires SKT to provide users with either a new handset or a 300,000 won ($251) subsidy as well as two years' discounts.

Rival LG Uplus, with 476,000 2G users, has not yet sought permission to terminate the service but is expected to begin the process shortly. The third player, KT Corp, shuttered its network in 2011.

The case for terminating 2G isn't complex. The legacy networks eat up operating and energy costs and occupy valuable spectrum.

But whereas South Korea's 2G subs account for just over 1% of the customer base, operators in neighboring China have their work cut out for them. Around 273 million people, or 17% of all mobile subs, still use a 2G service.

Both China Unicom and China Telecom reportedly began moves to migrate off 2G as far back as 2018.

Unicom recently began decomissioning GSM equipment in several provinces, though it has not set any timetable or made any public announcement about moving customers off the network.

All three Chinese operators ran a 2G migration campaign about two years ago, offering low-cost 4G devices and packages, with limited success, according to an analysis published by C114.

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The study found that most of the users are in rural or remote mountain areas, with limited discretionary income and where 2G is often the only network available.

China Mobile faces an even bigger challenge – not just because of the 200 million or so subscribers that rely on its GSM network, but also because it supports a burgeoning IoT business.

The market leader has taken the first step in terminating its GSM service, saying it will stop adding 2G IoT users this year.

According to an internal document leaked last week, it has set a target of building 118,000 new NB-IoT basestations this year, taking its total to 350,000.

The MIIT has stepped in to force the pace, issuing a directive in May that requires NB-IoT in all major urban areas by year-end. It targets 1.2 billion IoT connections by the end of 2020 as well.

— Robert Clark, contributing editor, special to Light Reading