An Oyster card is a contactless smartcard used for travel on public transport in London. It can be used to pay for travel on the Underground, buses, trams, DLR, London Overground, and National Rail services within the Greater London area. To check the balance on your Oyster card, you can use one of the following methods:
Online: You can check your Oyster card balance online by visiting the Transport for London (TfL) website. You will need to enter your Oyster card number and the password you created when you registered your card.