"They spent six days at a private home and were able to go totally off the map," the source adds. "No work or social media, it's just what their family needed. Kanye brought his friend, Don Crowley, along with his family. The children had a great time. They hung around at the pool most of the day."
The source also tells ET that they stayed at the home of Mike Meldman, the third owner of Casamigos Tequila with Rande Gerber and George Clooney. Kim has stayed at the locale before, as well as sister Kourtney Kardashian.
Kanye officially turns 40 on Thursday, and Kim's only posts leading up to the big day so far have been a throwback of her and her husband, aptly captioned, "Almost your birthday," as well as a sweet plane pic with the couples children, 3-year-old North and 18-month-old Saint, apparently leaving the family birthday-cation.
Kanye has taken a sabbatical from public events in the wake of his and Kim's traumatic past year, which included his wife being robbed at gunpoint in Paris, as well as his hospitalization shortly thereafter. So it's no surprise that this birthday was decidedly more low-key. It's a stark contrast to past birthday's Kim has thrown the rapper, such as his 38th, where Kim rented out Staples Center in Los Angeles, organizing a star-studded pickup basketball game that included John Legend, Justin Bieber, and several NBA stars -- from James Harden, to Kobe Bryant, to Magic Johnson and more.