The couple, who announced their separation in June 2015, were seen boarding a private plane to Yellowstone National Park, a source told ET.
Two of their children, 7-year-old daughter Seraphina and 3-year-old son Samuel, accompanied them, but their oldest daughter, 10-year-old Violet, reportedly did not travel with the family.
The vacation doesn't signal a romantic reconciliation, however, but rather is likely taking place around Valentine's weekend due to their children's schedules. Many California schools take a break around in mid-February for Ski Week.
The divorce comes after 10 years of marriage for the A-list couple. Affleck was rumored to have cheated on Garner with their former nanny Christine Ouzounian, a claim Affleck’s camp has vehemently denied.
"The story is complete garbage and full of lies," Affleck's rep told ET at the time, adding that "all allegations of a romantic relationship are baseless and untrue."
Check out more of the couple’s post-split friendliness in the video below.