Pay As You Go
Top up when you need it, pay only for what you use. PAYG is the most flexible UK mobile option — and the one that opened mobile to the mass market in 1997.
Pay As You Go (PAYG) is a mobile service arrangement where you add credit to your account in advance and pay for usage as it happens — with no monthly contract, no minimum commitment, and no direct debit. You cannot receive a surprise monthly bill because you control when and how much you top up. PAYG was introduced to UK mobile in the late 1990s and was the mechanism that made mobile phones accessible to the mass market for the first time — removing the credit check, long-term contract, and monthly billing barriers that had previously confined mobile ownership to the more affluent.
There are two distinct ways PAYG works in 2026. The traditional model charges you a per-minute rate for calls, a per-text rate for messages, and a per-MB (or per-session) rate for data from your stored credit. This is very expensive if you use your phone regularly — data charges on traditional PAYG can be many times the equivalent cost per GB of a monthly plan. Traditional PAYG is only cost-effective for people who genuinely use their phone very infrequently.
The modern approach — used by most people on PAYG — is a 30-day bundle: you top up a fixed amount (e.g. £10, £15, or £20) and receive a monthly allowance of data, calls, and texts. When the 30 days expire, you top up again to renew the bundle. Some networks auto-renew the bundle if you have sufficient stored credit; others require a manual top-up. This gives you the predictability of a monthly plan with none of the contract commitment. O2's Big Bundles, Three's PAYG plans, and Giffgaff's Goodybags all follow this model.
O2's PAYG is particularly notable because it includes free EU roaming up to 25GB per month — the same benefit included on O2's Pay Monthly plans. This is exceptional value for a no-contract product, making O2 PAYG an excellent choice for light UK mobile users who travel to Europe occasionally and don't want a full monthly contract. O2 PAYG Big Bundles also include data rollover — unused data carries forward to the following month.
PAYG suits children getting their first phone (parents control spending by controlling how much credit they add); elderly or very light users who genuinely use a phone infrequently and would waste a monthly plan's allowance; anyone who cannot pass a credit check and is therefore ineligible for Pay Monthly; people who need a temporary or secondary UK number — for example, international visitors, people between homes, or those who want a separate work number without a full contract; and people who value total flexibility above everything else and want to be able to change their phone or number freely at any time. For regular users, a 30-day rolling SIM Only plan is almost always cheaper per GB than PAYG, even accounting for the rolling plan's monthly price.
5G is available on PAYG with a compatible device in a 5G coverage area from EE, O2, Three, and Tesco Mobile — no extra charge for 5G access. Note that Three's PAYG plans from April 2026 are speed-capped at 25 Mbps (50 Mbps with an Auto-Renew Data Pack). O2 PAYG includes free EU roaming up to 25GB per month and has no 5G speed cap. EE PAYG has no speed cap.