While Tom Brady is gearing up for his first season as an NFL announcer ... his ex-wife, Gisele Bündchen, is enjoying herself by water-biking with her man, Joaquim Valente -- and interestingly enough, they rode right by the former quarterback's house!!

The 44-year-old model was spotted out on the Miami waters alongside her jiu-jitsu instructor-turned-boyfriend ... and their route led them through the waters near TB12's pad.

Of course, the exes are neighbors of sorts ... as Gisele's $11 million home is pretty close to Tom's. It's unclear if Brady was home during their water-biking fun ... but we're hoping for his sake he was elsewhere.

Bündchen rocked a tiny black top with a leopard-printed skirt for the outing ... and Valente elected for camo-printed trunks and a ballcap.

This isn't the first time we've seen the couple take part in activities out on Miami's waters ... in June, they picked up the paddleboards and took them out for a spin -- alongside Tom and Gisele's kiddos.

It also further proves the two are very much still in a relationship ... as rumors were swirling earlier this year that they were dunzo, but clearly, they're going strong.