Buses are the cheapest way to travel from Cambridge to London, with daily direct connections leaving throughout the day. National Express is the only operator on the route, but they run plenty of buses. The first service leaves as early as 3:05 a.m., and after that there are departures every hour until 9:30 p.m. The journey takes around 1 hour 45 minutes, with no changes. All buses leave from Cambridge Coach Station, which is right next to Christ's Pieces, close to the centre of town. Park and Ride buses stop at the coach station, so anyone coming from the outskirts of Cambridge can easily reach their bus. However, for very early departures, it will probably be necessary to book a taxi.

Catching a train is the quickest way to reach London from Cambridge, with hourly services into London Kings Cross or London Liverpool Street from Cambridge Station. Train services are operated by Great Northern and Abellio Greater Anglia and take just an hour (or just over) to reach London. Services start before 6:00 a.m., and the last train leaves at 11:30 p.m. Getting to Cambridge Station is located a mile away from the centre of town, but buses run straight to the station entrance from central locations. Trains run into London Kings Cross or Liverpool Street, but you can also alight at Finsbury Park or Potters Bar, if you need to reach destinations in north London or Hertfordshire.

Travelling from Cambridge to London by train is the most popular option. The prices are reasonable in comparison to the bus and the journey is significantly quicker on the train.