Ezekiel Elliott had his good time temporarily ruined again this week ... only now it was by the U.S. Coast Guard during a rager yacht party in Miami.

Ezekiel was partying with friends and a gaggle of chicks Saturday on a yacht called No Rules II, when a Coast Guard cruiser pulled up. We're told the yacht had docked minutes before.

Eyewitnesses tell us 2 guards boarded the yacht and conducted a 20-minute search on-board. We're told once the search was complete, the guards went back to their vessel and took off.

Elliott's attorney tells TMZ Sports the Coast Guard boarded the yacht to make sure there were enough life jackets onboard. He says no citations were issued, and the party continued.