3HK DIY

3HK DIY is not a travel eSIM store — it is a Hong Kong carrier's official prepaid product, and that is exactly its value.

For visitors to Hong Kong, a DIY SIM gives you a real local 3HK number with local rates, supported by a physical retailer network (convenience stores, MTR shops) for top-ups, plus real-name registration handled in the app as HK law requires.

For Hong Kong residents, the DIY app doubles as a roaming manager: buy destination day passes (mainland China, Macau, Japan, Korea, Taiwan, Southeast Asia and more) that bill to your existing SIM, often cheaper than travel-brand eSIMs on the same 3HK network infrastructure. Plan selection, purchase and activation all happen inside the app rather than on a public web catalogue, which is why no static price table is published here. Trade-offs: coverage is Asia-centric (mainland China, Macau, Asia day passes), the experience assumes the app and registration flow, and it lacks the instant-QR simplicity of global eSIM brands. But if your trip is Hong Kong-centric or you want an official local number, it beats generic travel eSIMs on local rates and physical availability.

Mainland-China roaming and keep-alive (official 2026-09 wording + community)

How to buy China data: the official DIY app/web configurator sells custom travel passes for Asia-Pacific (mainland included) from HK$13/day plus HK$8 per extra 500MB, valid up to 180 days (verified on the official travel page, 2026-09). Greater-China 365-day passes (e.g. 40GB+5GB social) circulate via resellers at roughly ¥320-368 — the 365-day tier is a reseller listing, not the official configurator default.

Keep-alive (community wording, terms not independently verified): stored value and pass validity are linked; resellers cite roughly HK$200/year in top-ups to keep the number. SMS receiving in the mainland is free, sending HK$3.5, calling the mainland HK$6/min (reseller wording). Keep-alive users should check the balance expiry in the app every 90-180 days and complete a top-up or pass purchase inside the window.

Using it in the mainland: enable data roaming on insertion; mainland roaming rides all three Chinese networks with a Hong Kong mobile exit; VoLTE required; works for verification SMS. Real-name registration per HK law happens in the app (unregistered SIMs cannot receive SMS); passport and China travel permits are accepted.

Real-time pricing lives in the official app; figures here verified 2026-09.