There is no public transport as such, excluding shuttle buses running between hotels and the Duty Free shopping center in Garapan.
By taxi
Taxis on Saipan are expensive but plentiful, however the only place they are allowed to pick up or drop off passengers is at the airport or a hotel, and sometimes at DFS. There is also a large network of illegal taxis run by Chinese and Korean immigrants, that will take you anywhere for less than $5.00. For some Saipan residents this is their only means of transportation.
Because Saipan is so small, taxis from the airport to the main hotel area of Garapan can run upwards of $25-30, so plan ahead by arranging transportation through your hotel, which often charge $10 per person flat rate.
By bus
There is no public bus service on Saipan, but on Saipan PDI and other companies run a shopping shuttle bus to and from the Duty Free mall DFS Galleria in Garapan. DFS also has their own free shuttle from most of the major hotels.
By Moped
Mopeds can be rented for about $20, though roads are very dark at night and bugs predominate after dusk. Therefore, consider mopeds for day-tripping only, as drivers tend not to give heed to mopeds or bicyclists throughout the CNMI or Guam.
By car
Car rental is a good option for getting off the beaten track, as roads are generally quite good. Most car rental offices are either at the airport or at major tourist hotels; some offer a free pick up and drop off service.