The eSIM for Spain provides you with access to 2 to 50 GB (depending on the plan chosen), without physically changing the SIM card in your phone.
The eSIM plan is valid for 28 days and also provides you with Free Incoming calls (with UK based mobile number) in addition to the data.
In order to purchase the eSIM, just complete the transaction here and an eSIM QR code will be emailed to you in the next 30 minutes with instructions to install on your phone.
Once installed, you can start using data on the eSIM in Spain immediately. The validity of the eSIM shall start from the day when you start using it in Spain.