There are no trains in the Bailiwick except a spur on Alderney; roads are small but not busy. No island is very big, so a bicycle is a good way to get around.
Alternately there are hire cars, taxis and a frequent bus service during the day available on both Guernsey and Alderney - other islands have no motorcycles, private cars or buses. Buses cost £1 no matter where you go on either motorised island. Most roads have no pavements and the few that do can legally be driven on by motorists. It is also legal to not wear seat belts whilst in the back seat of a car.
The other Channel Islands can all be reached by ferry from St Peter Port. Jersey and Alderney can also be reached by plane.