SIM Buying Guides

Annual price adjustments explained

Every tariff rises once a year. Here's exactly how the increase is calculated on each network and how much notice you get.

By SimDeals·Updated 30 July 2026·5 min read

A SIM only price is a starting price, not a fixed price. Every network applies an annual increase, and the way that increase is worked out differs from network to network. Here is how each one does it, when it lands, and how to factor it into a fair comparison.

Key takeaways

All tariffs are subject to one increase a year.
O2 and Vodafone use RPI or CPI plus any adjustment the network applies.
EE applies a flat 75p increase instead of an index-linked one.
You get at least 30 days' notice of any price or tariff change.

How the increase is calculated

On O2 and Vodafone the annual increase is linked to an inflation index — either the Retail Price Index (RPI) or the Consumer Price Index (CPI) — plus any additional adjustment the network chooses to apply on top. Because the index is published each year, the exact figure is not known in advance.

EE takes a different approach: a flat 75p added to the monthly line rental. It is not linked to inflation, so the cash amount is known up front even though the percentage impact depends on how much you pay.

O2 — RPI or CPI plus any network adjustment
Vodafone — RPI or CPI plus any network adjustment
EE — flat 75p per month

The notice you get

At least 30 days' notice is given before any price change takes effect. That notice applies to tariff changes as well as price changes, so you are told before anything on your plan moves.

Keep the notification. It is the simplest record of what your line rental was before the change and what it becomes afterwards.

What it means over a 24 month term

A 24 month agreement spans two anniversaries, so a headline price will normally move twice before the term ends. This is true of every network and of buying direct as well as buying through us, which is why comparisons are fairest when they line up starting prices on like-for-like allowances.

A flat-rate increase such as EE's 75p hits low-priced plans harder in percentage terms and expensive plans more gently. An index-linked increase does the opposite in cash terms: the more you pay, the more you pay again.

How to compare fairly

Compare the starting monthly price on the same data allowance and the same term, then treat the annual increase as a known feature of every plan rather than a differentiator. Where a plan is genuinely cheaper on day one, that gap does not disappear at the anniversary — the increase is applied to a smaller base.

Our deal pages show the starting price including VAT, and where we can we show the same allowance at the network's own published price for context.

Frequently asked questions

Can I leave if my price goes up?

The increase is a contractual term of the tariff rather than a change imposed outside the agreement, so leaving before the minimum term ends still triggers the usual early termination or cease fee. Check your notification and your terms before requesting a cease.

Does the increase apply to 30 day rolling plans too?

All tariffs are subject to the annual increase, with at least 30 days' notice. On a 30 day term you have the flexibility to change plan, but a £30 cease fee applies if the connection is disconnected within 24 months of activation.

Is the increase applied to the ex VAT or inc VAT price?

It is applied to the line rental, and VAT is then charged on the new figure. Business and mobile broadband cards on this site show both the ex VAT and inc VAT price so you can see the effect either way.

Deals mentioned in this guide

Prices include VAT and show the saving against the network’s own published price where a like-for-like plan exists.

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