The classic "data-only SIM" is quietly dying in Hong Kong — not because it stopped existing, but because a HK$33 prepaid card from SoSIM now does everything a data-only line used to do, for a fraction of the cost. At the budget end there is basically no "voice vs data" pricing gap left; the difference now is fit — which device the SIM lives in, and what you actually need it for.
The HK$33 card that changed the game
SoSIM runs on 3HK towers, and its HK$33 starter card packs 50GB of 4.5G data (FUP) plus 1,500 voice minutes for the first 30 days — then you keep it alive with cheap monthly combos. The part tablet and router users care about: SoSIM explicitly allows the card in other devices, routers and smartwatches, supports hotspot sharing, and only throttles to 128kbps after you burn through the fair-use cap. Want one number feeding several gadgets? SoSIM sells a supplementary SIM (附屬卡) that shares the main card's data and minutes for HK$28 per 30 days or HK$168 per 360 days.
| Option | Network | What you get | Price |
|---|---|---|---|
| SoSIM starter card | 3HK | 50GB FUP + 1,500 min, 30 days; router & hotspot OK | HK$33 |
| SoSIM supplementary SIM | 3HK | Shares main card data + minutes; physical or eSIM | HK$28 / 30 days; HK$168 / 360 days |
| Club SIM monthly | csl | 20 / 40 / 80GB @ 42Mbps + unlimited local voice, no contract | from HK$58 / month |
| 3HK 5G SIM-only | 3HK | 30GB 5G, online promotion | from HK$100 / month |
| Market floor (2026) | mixed | Cheapest 30-day cards from ~HK$19; annual 12GB cards from ~HK$30 | as of 2026-08 |
How a data-only SIM differs in practice
- Voice: on a strict data-only SIM there is no calling number — dialling out fails or is blocked. SoSIM and Club SIM actually bundle a number, so they sit halfway between a data card and a full plan.
- SMS: after real-name registration, most local prepaid cards still receive SMS — the thing you need for bank one-time passwords. Ultra-cheap data-only travel cards sometimes cannot, so check before relying on one for 2FA.
- Devices: the same SIM slides into a phone, a tablet or a 5G router. Phones auto-fill the APN; a router usually needs it set by hand.
- APN: 3HK / SoSIM use mobile.three.com.hk, csl / Club SIM use mobile, CMHK uses CMHK — no username or password in any case.
- Tethering: prepaid cards generally allow hotspot use (SoSIM is explicit about it); some 24-month contract plans restrict it, so read the fine print before putting a contract SIM in a router.
Broadband backup economics: a SIM in a 5G router vs a second line
| Approach | Rough cost | Notes |
|---|---|---|
| Second fixed line (e.g. HKBN 1000M) | ~HK$98 / month (36-month); ~HK$78 in new public-housing blocks | Full speed, but a 12-36 month contract you pay every month |
| 5G home broadband (e.g. 3HK FWA) | from ~HK$78 / month; most operators under HK$200 | No wiring, plug-in 5G router provided; entry tiers are 300-500GB then unlimited 4.5G |
| Data SIM + your own 5G router | ~HK$33-58 / month for backup-only use; router one-off ~HK$300-1,500 | Pay only when you actually need it — ideal failover, not a daily driver |
For a true failover — the internet drops a few times a month and you just need to keep working — the SIM-plus-router route wins on cost: HK$33-58 a month and only when you actually use it, versus HK$98-150 for a second line you pay for every single month. The moment you are pulling 100GB+ every month from that router, step up to a real 5G home broadband plan or a generous unlimited plan — the fair-use caps on cheap cards will not keep up.
Prepaid validity, top-ups and real-name rules
- A new SoSIM card is valid for 120 days from activation; topping up at least HK$20 extends it, and you can switch on auto-renew so a 30-day combo simply rolls over.
- SoSIM's So+ add-on keeps the number alive for HK$5 per 30 days (or HK$60 for 360 days) — handy for a backup SIM you barely touch.
- Since 1 September 2021, every SIM used for local data, voice or SMS must be registered under the Telecommunications (Registration of Subscriber Identity Module Cards) Regulation — so that HK$33 card needs your HK ID or passport details before it works here.
- Data value swings wildly: the 2026 market floor is roughly HK$19 for the cheapest 30-day card and HK$30 for an annual 12GB card, while 5G cards still cost noticeably more per GB than 4.5G ones.
eSIM for tablets and laptops
Every cellular iPad and most modern Windows laptops take an eSIM, and the local operators now sell them at the same prices as plastic: SoSIM sells a new eSIM at the same HK$33 price (converting an existing physical card costs HK$28), CMHK supports eSIM on MySIM and its prepaid line, and Club SIM runs on the same csl eSIM system. For a tablet that never needs a phone number, installing a local eSIM beats hunting for a nano-SIM tray — and for a laptop, a local data eSIM plus the cheapest 5G SIMs list is a solid, hotspot-free setup.
Frequently asked questions
Can I put a data-only SIM in my phone?
Yes, it will give the phone mobile data, but a strict data-only card has no voice number. Realistically most HK budget cards (SoSIM, Club SIM) include a number anyway, so they work in a phone as a second line — just without the call minutes, or with a small bundle. A data-only SIM is best for tablets, routers and backup; for a primary phone you usually want a regular plan.
Do data-only SIMs work in a 5G router?
Yes — and that is one of the main reasons to get one. Put the SIM in the router, set the APN by hand (SoSIM / 3HK: mobile.three.com.hk, csl / Club SIM: mobile, CMHK: CMHK), and confirm the card allows hotspot or router use — prepaid cards generally do, while some contract plans restrict it. Check the host network is strong where you will use it before relying on it.
Is a data-only SIM cheaper than a normal plan?
Not by much at equal gigabytes — pricing tracks the data allowance, not whether voice is included. A HK$33 SoSIM card and a HK$33 SIM-only voice plan both give you roughly 50GB. The real advantage is fit: you add data to a tablet, router or backup line without paying for calling features you will not use, and prepaid means you only pay for months you actually need it.
Can a data-only SIM replace my home broadband?
As a full-time replacement, usually no — cheap cards carry fair-use caps and latency that get annoying with heavy streaming and gaming, and a 50GB allowance disappears fast with a household. It shines as a backup that kicks in when fixed broadband drops. If you want to actually replace the fixed line, look at 5G home broadband (from about HK$78 a month) — see our [5G vs fibre comparison](/guides/5g-home-broadband-vs-fibre).