Where can I get matching couple's t-shirts in Singapore?

What kind of designs are you looking for? Im not a big fan of matching couple tees but there are quite a number of shops selling them at Bugis+ as well as Far East Plaza :). They usually sell the cute-ish cartoon ones. If you're looking for a matching simple polo tee, places like Giordano and Bossini will not disappoint.

You can check out this website and see if any design catches your eye: http://mabeldress.com.sg/women/couple-wear/ They seemed to have quite a wide selection and in different styles. Hope you find one that you like! :)

you could find a few matching couple t shirts in https://shopee.sg/%F0%9F%92%9ENew-Couple-T-Shirt-King-and-Queen-Love-Matching-i.13353680.231592576

Agree on camouflage too! You are able to get matching family outfits

Camouflage at Bugis. They have family ones as well