This applies for Classic SIM only, on 4GB and 10GB tariffs.
Your Classic SIM plan runs in calendar months, meaning data allowances (including EU roaming) refresh on the 1st of each month.
The only exceptions are roaming outside of the EU, with you getting a new allowance each day.
What happens if I join mid way through the month?
If you join say half way through the month, we would only charge you half the price for that month. We therefore also provide half the monthly allowance, before your data fully refreshes on the 1st of the next month.
For example, if you joined on the 10GB plan on the 15th June (so 50% of the month remaining).
Your total charge for June would be 50% the full price.
Your data allowance would be 5GB.
On the 1st July, you would have 10GB allowance for July.