Here is the full list of all 17 Aqua Moto Racing Utopia achievements.
Complete all other Achievements
Complete the Tutorial
Win an event in a Championship
Own every watercraft
Win every Runabout Championship
Win every Ski Championship
Win gold medals in Time Trial mode on every Track
Win the gold medal in all Freestyle events
You must pass each buoy perfectly in a Championship race
In a Championship race, pass every buoy in 1st place and win
Jump over 40m
Perform every stunt at least once in a race
Perform every air stunt at least once in a Freestyle Event
Perform every water stunt at least once in a Freestyle Event
Perform 20 stunts during a Freestyle Event
Perform a Backflip with a Runabout watercraft
Find the ball of straw at each Venue