Justin Bieber Emerges From Lake in Dripping Wet Underwear, on Video

Justin Bieber's fans certainly don't need him to say "Sorry" for his new video ... 'cause they got the chance to ogle every bit of the guy -- including his "Peaches."

The singer-songwriter shared a clip to social media on Saturday from right after he jumped out of a body of water ... walking across the grass in a pair of wet tighty-whities that aren't doing a dang thing to cover his backside.

Check out the clip ... Justin's covering his you-know-what with his hand as he approaches -- but does nothing to stop his skin from shining through behind.

Ha laughs along with his buddies as he dries himself off ... and, it's worth mentioning that he seems to have worn boots into the water -- strange given he's not even wearing a swimsuit!

Justin and his better half Hailey have been enjoying a lot of fun in the sun this summer ... with HB stunning in a barely-there bikini on a European vacay just a couple months ago.

Plus, Justin was firing off bullets without a shirt on in a video earlier this month ... so, it seems he feels his best when he's wearing less!