Kylie Jenner and Timothée Chalamet Shop for Bikinis on Mexico Vacation

Kylie Jenner and Timothée Chalamet must've packed light for their trip to Los Cabos, because they went shopping for some sexy swimwear ... and it's all on video.

Check out this viral footage showing Kylie and Timothée browsing around a clothing shop in Mexico this weekend ... they go straight for the bikini section, and TC helps KJ pick out the perfect piece.

We saw Timothée wearing the same hat around a Cabo marina, and we've seen Kylie rocking a skimpy black swim top at their swanky, oceanfront resort ... but it's unclear if Kylie purchased that bikini on this shopping excursion.

As we first told you ... Kylie and Timothée had an intimate date night at Flora Farms in San Jose del Cabo ... and they also got close on a fancy yacht.