Keep Your UK Number Alive From Abroad: 12 SIM Keep-Alive Rules Compared (2026)

Before leaving the UK for good, the biggest risk to your British number is silent recycling — and with it, every bank, ChatGPT and app account tied to that +44 verification number. This guide compares the keep-alive rules of 12 UK SIMs in the simdirs directory (verified against official terms, 2026-09-26), ranked by annual parking cost and how hard they are to fumble.

Keep-alive rules at a glance

• giffgaff (O2): any account activity in 180 days — sending one £0.30 text counts. ~£0.60/year
• VOXI (Vodafone): activity every 180 days, £5 minimum top-up, reminder SMS ~90 days before expiry
• Three: PAYG needs one chargeable event per 180 days — one text is enough
• CTExcel (EE, China Telecom): any chargeable event in 180 days — texting BAL to 888 for a balance check counts. Zero extra cost
• Tesco Mobile (O2): usage once every 6 months — the loosest cadence, but note this is the official disconnection clause: exceeding it can forfeit both number and credit
• Vodafone: 90+90 structure (warning at 90 days of inactivity, disconnect at 180) — treat as 180 days
• Lebara: two layers — credit lapses after 90 days without top-up, but the number survives 365 days of inactivity; £5 per top-up
• iD Mobile (Three): SIM expires after 90 days without use (terms say 4 months) — the strictest tier
• Lycamobile: 90 days + 30-day grace, £10 per top-up, £40+/year — only worth it for international minutes
• TalkHome: contract-based (£5/month); PAYG line has its own rules — contracts are the wrong tool for parking
• CMLink (EE, China Mobile): 90 days after plan expiry for monthly/annual plans, but 30 days only for one-off China bundles — the tightest window, set a reminder
• CTE UK: 90-day activity rule, 30-day rolling bundles

Choose by scenario

Pure parking (a few verification SMS a year): giffgaff wins outright — two £0.30 texts a year, and prepaid credit sits indefinitely. Runners-up: VOXI (proactive reminder SMS makes it hard to miss) and CTExcel (free balance-check SMS renews the window).

Parking + China roaming data: CMLink or CTExcel. CMLink adds 5G and a reported Hong Kong residential IP landing; CTExcel is cheaper per GB on a 180-day cycle. Full breakdown in CMLink vs CTExcel compared.

Parking + light UK usage: Tesco Mobile (loosest 6-month cadence) or Three PAYG (text-level cost per 180 days).

Not recommended for parking: Lycamobile (£40+/year), iD Mobile (strict 90 days), any 12-month contract.

Failure-mode ranking

1. Tesco Mobile (6-month window)
2. giffgaff / VOXI / Three / CTExcel / Vodafone (180-day window; VOXI and CTExcel send official reminders)
3. Lebara (two-layer protection: credit can lapse without losing the number)
4. iD Mobile / CMLink one-off bundles / CTE (90/30-day windows — calendar reminders required)

General notes

• “No usage” clauses count chargeable events: receiving SMS usually does not count; sending texts, using data or topping up does (check each profile for the exact wording)
• Switching phones with an eSIM may require reactivation on some carriers — avoid device changes inside a keep-alive window
• Policies change: verified 2026-09-26, confirm against official terms pages before acting; if you spot a rule change, the comment section is open

Full profiles and current prices for all 12 cards are in the SIM directory.