The supermodels are both featured in the magazine in a series of seriously sexy photos where they pose in skimpy bikinis that don't always include tops.
Graham, 30, hit the beaches of Nevis in the Caribbean for her photo shoot, while Upton, 25, was in Aruba.
It's clear in these SI videos that Upton and Graham are quite comfortable in scantily clad swimsuits.
Danielle Herrington is this year's cover girl, and Graham, 30, shared a sweet message for the 24-year-old model. "DANIELLE!!!! Tears of joy for you this morning!" she posted to Instagram. "Congratulations on breaking even MORE barriers being the 3rd black woman to ever grace the cover of @si_swimsuit! I have so many emotions? SOAR BABY GIRL!!"
In addition to Herrington, Upton and Graham, Christie Brinkley's 19-year-old daughter, Sailor Brinkley Cook, is also featured in this SI issue and revealed to ET why she did not tell her supermodel mother that she was posing nude in the magazine.