The Duke of Sussex got his polo on Friday during a match at the Santa Barbara Polo and Racquets Club, where we're told he played on a team called Los Padres (the green jerseys, it seems) alongside a pal of his ... and apparently this happened last minute.

In any case, Hare clearly needed to stretch it out before getting on the horse to ride -- and he did exactly that ... with some mid-level squats, and extra effort to work out his glutes.

Of course ... his wife, Meghan Markle, was also there to watch her prince do his thing -- and once Harry was on the field ... it appears he saw some serious action. The dude's been playing a long time, BTW, dating back to his youth ... so the sport comes naturally.

This has gotta make him feel right at home ... which is nice, since he's sorta keeping London at arm's length at the moment -- this following his brief visit recently to see meemaw.

He told Hoda Kotb not too long ago that he misses his family ... but dodged the follow-up when his brother and father were specifically brought up -- alluding to the ongoing rift.