The reality star rented out Six Flags Theme Park for the pair to enjoy with their friends and family.
And this weekend Jenner, 20, has been sporting a sporting a head-turning diamond ring on her wedding ring finger sparking rumors that the pair may now be engaged.
The theme park in Valencia, California, was closed off to the public earlier this week so that the make-up mogul could enjoy it with her family and boyfriend.
It's understood they took their three-months-old daughter, Stormi, along for the fun day although she is too young to ride on any of the roller coasters.
Kylie shared clips from the park via her Social Media as they can be seen screaming while on the Superman coaster, which reaches speeds of 100mph.
The party enjoyed VIP treatment for the day while it is understood that it took a six-figure sum to rent the park out.
On Saturday the make-up mogul set tongues wagging while shopping in Los Angeles as she sported a double diamond band around her finger.
There has been growing speculation in recent weeks that the couple was getting engaged after she gave birth to their baby daughter Stormi.
RadarOnline.com reported recently how Kylie had vowed to shed more than 20lbs in weight since giving birth to her first child.
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