Although your network will often allow you to upgrade with them well in advance of your contract end date, you can only switch to a new network freely once your current contract ends. You can look to switch with a free Porting Authorisation Code (PAC) any time in your final month but your new contract will begin as soon as you buy it, so be careful not to pay twice in your final few weeks.
To find out when your current contract ends, Simply text 'INFO' to 85075. Your current provider is required to send you a response with the requested info within one minute. The reply from the provider must contain any relevant information about early contract cancellation charges, as well as any remaining balance on the account for Pay-As-You-Go customers. You will still need to call your provider if you have more than one connection on the same contract.
If you want to switch sooner or you believe you can save more by switching than you’ll pay to leave your current contract, see our guide on leaving before your contracf expires.
If you want precise details on how to switch and keep your current mobile number, see our guide on switching.