Matt showed off his fit physique in neon green swim trunks while Rachael sported a cheetah-print bikini top with black shorts and sandals.
Matt was also caught sweetly embracing Rachael at one point while she was scrolling through her phone.
"Matt is truly in love with her," the E! News source said. "They have a special bond and have really turned a leaf in their relationship."
Matt and Rachael fell in love on The Bachelor's 2021 season, which filmed in late 2020.
But then Matt revealed on The Bachelor: After the Final Rose he had broken up with Rachael in February -- shortly after Rachael apologized for her racially-ignorant and insensitive actions in the last several years -- to allow the Georgia native some time to educate herself on racism in society and become a better person with more awareness.
"They are back together, but Matt is hesitant to publicly and outrightly confirm it right now because it's still fresh and they still have issues to work through... He's feeling pressure to set a good example for other Black men," a source recently told Page Six.
Matt confirmed to People late last month he's "not pursuing any relationships right now outside" of his with Rachael, who has defended Matt against harassment and called him the love of her life.
When People asked Matt whether Rachael has done the work she promised, Matt replied, "That's something you could talk to her about."
And Matt told WSJ Magazine earlier this month he and Rachael are "trying to make it work" and are having "critical conversations" about what it means to be in a biracial relationship and what Matt needs in a partner, "especially if that woman isn't Black," to understand his perspective.
"It's on people who care about being allies to do the work to be truly antiracist," Matt said. "And I think it's unfair to leave people without the ability to unlearn and be better."
Matt and Rachael's apparent April reconciliation came about a week after Us Weekly reported the pair were "on non-speaking terms" due to The Bachelor star's alleged attempt to two-time Rachael.
Matt was accused of "trying to hook up" with a woman named Grace in Florida on April 4 and treating her like "a booty call" before reuniting with Rachael in New York only two days later, according to Carbone.
A source told Us last month that Rachael thought she and Matt were on the track to getting back together but once she found out about Grace, she felt "manipulated," "played" and "devastated" by her then ex-boyfriend.
However, Matt clearly asked for forgiveness at some point and Rachael decided to give him another chance.