How do I sign up to GAMSTOP? How do I sign up to GAMSTOP? To sign up for GAMSTOP, visit https://www.gamstop.co.uk and register your details. You can also call them for free on 0800 138 6518. Lines are open seven days a week from 8am to midnight. If you need assistance, please click here to see our contact details. Related articles Will GAMSTOP close accounts I already have or just new ones? I didn’t self-exclude via GAMSTOP but it says I did. Who do I contact? What is GAMSTOP?