Gwen Stefani and Blake Shelton go skiing and tubing with the kids in Utah

The couple went to Woodward Park City Ski Resort in Utah for Frida and Gwen's three boys on Saturday — and the whole family was out and about, tubing one day… and skiing the next. In photos obtained by TMZ, you can see GS and BS walking hand-in-hand with the teens near the back.

Eyewitnesses told us that the family was not ashamed of the attention they attracted, and were not opposed to taking pictures with fans… by all accounts, they were absolutely thrilled.

Interestingly, it seems like it's Gwen who took it down the hills here — on Friday, she could be seen tubing with her boys, while Blake looked on and filmed. On Saturday, she and the kids went sledding…and we're told Blake didn't show up. Looks like she's active!

Anyway, like we said… these lovebirds won't be next to each other by midnight next week — because Blake is booked to perform in Nashville, and she's set for a gig in Vegas.