Bill Belichick has himself a catch in Jordon Hudson, literally ... 'cause the immortal head coach and his 24-year-old girlfriend debuted a couples-themed costume this Halloween!
Jordon and Bill posed for a few sandy snaps in the Atlantic -- with BB dressed up as a fisherman, and Hudson as a mermaid.
BB and JH are both sporting huge smiles ... and it's crystal clear they're enjoying the spooky day together!
Of course, TMZ Sports broke the story ... Belichick and Hudson met on a flight in 2021, where they became fast friends.