News · 10 November 2026
O2's Black Friday SIM deals: what £19.99 unlimited really costs
O2's Black Friday sale started on 5 November 2026. Its headline SIM-only deals are Unlimited Plus at £19.99 a month and 75GB (Classic) at £18 a month, both on 24-month contracts. Both go up by £2.50 every April, so you pay more than the headline. Over 24 months the true monthly cost is about £22.70 for unlimited and £20.71 for 75GB.
By The SimSift team · Published · Figures checked 10 November 2026
What changed
O2 says on its Black Friday page: "Our Black Friday sale started early this year on 5 November." For SIM-only it advertises its "lowest-ever price on Unlimited Plus" on a 24-month plan, with Disney+ or Amazon Prime included for six months, and the 75GB Classic plan at £18 a month ("Rises to £20.50 Apr '27, £23 Apr '28") (O2 Black Friday).
Who it affects
- New O2 customers, or anyone whose current contract is ending soon.
- Existing O2 customers thinking about upgrading. Check My O2 for your own offers.
- People who stream, tether a laptop or use a lot of data (Unlimited Plus).
What it costs (true monthly cost)
We assume a new 24-month contract with the first bill in November 2026: 5 bills at the starting price, 12 bills after the April 2027 rise, then 7 bills after the April 2028 rise.
| Plan (24 months) | Starting price | From April 2027 | From April 2028 | Total over 24 months | True monthly cost |
|---|---|---|---|---|---|
| Unlimited Plus | £19.99 | £22.49 | £24.99 | £544.76 | £22.70 |
| Classic 75GB | £18.00 | £20.50 | £23.00 | £497.00 | £20.71 |
Things to watch:
- The £2.50 April rise is in the contract. It's not a surprise rise, so it doesn't give you a penalty-free exit.
- Disney+ or Prime is free for six months only. Cancel it before it starts charging if you don't want it.
- O2 includes up to 25GB of EU roaming, which is a real saving if you travel. EE and Vodafone charge a daily fee on most plans.
- O2 is a credit-checked pay-monthly contract.
- O2's Black Friday page is clear that many phone deals end on 2 December. It is not as clear about a closing date for these SIM-only prices, so check the offer is still current before you buy.
What to do
- Compare true monthly cost, not the headline. £19.99 becomes £24.99 by the end.
- If you hate price rises, look at SIMs that keep the same price for the whole contract. Some run on O2's own masts.
- Check O2 coverage where you live with Ofcom's Map Your Mobile before you switch.
- Switching is free: text PAC to 65075 to keep your number.
Compare on SimSift
Sources
- O2 Black Friday page (primary)
- O2 Pay Monthly SIMs (Unlimited Plus £19.99 / £22.49 Apr '27 / £24.99 Apr '28; 75GB Classic £18 / £20.50 / £23)
Figures checked 10 November 2026 against O2's own pages.
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