This note is based on BankNav’s free Giffgaff SIM and activation tutorial. Source:

Giffgaff is a UK MVNO on O2’s network. It can work as a low-cost backup UK number. The source highlights 0 monthly fee, free incoming SMS, pay-as-you-go data, a 10 GBP first top-up, and a first-top-up bonus. Always verify current bonuses and retention rules on Giffgaff before acting.

Ordering the Physical SIM

The source article included referral-style order links; I do not keep them here. Use the official Giffgaff pages first:

Check the country list and delivery notes on the live order page before using it from mainland China. If the page first shows paid bundles, choose No thanks, I just want a free SIM when available, then fill in the shipping information.

Important detail: add your mainland China phone number after the address. The card ships by UK ordinary mail, and the source says missing phone information may affect delivery. Expect a long wait; the source says around one month.

Before Activation

Prepare:

  • Giffgaff physical SIM;
  • 6-digit or 13-digit activation code on the SIM;
  • email inbox for verification;
  • a real Visa or Mastercard credit/debit card;
  • a billing address that is reasonably consistent.

The source warns against using virtual cards such as xPay or “little red card” style products for top-up, because they may increase account-risk issues. This is user experience rather than an official guarantee, but using a real card is safer.

Activation Flow

Open:

Flow:

  1. Enter the 6-digit code on the SIM front or the 13-digit code on the back.
  2. Click Activate your SIM.
  3. Register with email and verify the email code.
  4. Set a password. The source recommends at least 12 characters with uppercase, lowercase, and symbols.
  5. At the plan prompt, choose No, thanks.
  6. At the bottom of the plan page, choose Pay as you go No monthly plan.
  7. First top-up is at least 10 GBP, paid with Visa / Mastercard.
  8. Fill in address and card details, then submit activation.

The source also mentions buying an official top-up voucher:

After successful activation, Giffgaff assigns a UK number. A local format like 07123456789 becomes +44 7123456789 for international use: remove the leading 0 and add +44.

180-Day Retention

The core rule from the source: the account balance must change at least once every 180 days, otherwise the number may be reclaimed.

Low-cost method: send one outgoing SMS. The source records about 0.30 GBP per SMS to mainland China while roaming, or about 0.08 GBP through Wi-Fi Calling. The first top-up also counts as balance activity, so the initial retention period starts from activation/top-up.

Practical habits:

  • screenshot the number, balance, and activation date;
  • set a reminder around day 150;
  • screenshot the balance change after retention activity;
  • test signal and SMS before travel or device changes.

Notes

Giffgaff is useful as a low-cost UK number, but it is not maintenance-free.

Watch for:

  • slow international mail delivery;
  • payment method risk during activation;
  • platforms that reject Giffgaff or prepaid numbers;
  • balance activity, not just incoming SMS, for retention;
  • long idle periods without testing signal;
  • extra risk if you later switch to eSIM through unofficial methods.

References