Sea Vessel Passage
price
1 per 50 miles
Planets with large bodies of water often develop extensive commerce and transit networks by ship, hovership, and even submarine. This transport is slower than travel by plane, but cheaper per mile (and considered more relaxing by many travelers). Some planets have rigid lighter-than-air vessels as well, such as dirigibles, which tend to have similar accommodations, pricing, and speeds.
Source
Core Rulebook pg. 235