Girls' trip! Kourtney Kardashian sure knows how to celebrate turning 40! Pack your crew into a private jet and head south to the Caribbean -- Turks & Caicos, Aman Resort, to be exact ... bring the bikinis, the sexy eveningwear, your sister's baby and a nanny and enjoy!

Kourt brought along the whole gang for a beachside birthday blowout in the sunny resort spot and we are JEALOUS!

Of course the Instagrams are all about the boobs and butts and beautiful looks ... except Khlow's adorable shots with baby True. Our hearts are melting! Check out the whole gallery below!