Tickets And Passes
You are required to have a ticket on you at all times while on the London Underground. Not only are there ticket checks that will incur a £80 penalty if you fail to produce a ticket, but you'll also need a ticket to exit the station at the end of your trip.
1) Fares
Single fares for most destinations in London are £4.90 for adults. If you're traveling further out of the city, your fare may be higher depending on the zone you travel to. You should, however, consider buying an Oyster Card as fares are only half price when using the card.
2) Oyster Card
Almost everyone who uses the London Underground, tourists and locals alike, use an Oyster card. It's a permanent reusable electronic ticket that can be topped up whenever needed. Fares for most destinations in London are just £2.40 for adults when using the card.