The nearest station to the Royal Free Hospital is Belsize Park station, on the Northern Line. The walk from Belsize Park station to the Royal Free Hospital takes seven minutes. It is partly uphill.
Hampstead Heath station is very near to the hospital and is on the London Overground network. The station accepts Oyster cards.
There are lots of buses that pass by the Royal Free Hospital. Bus routes 24, 46, 168, 268 and C11 all serve the hospital.