The family-of-three were spotted walking around Santa Monica, where Heidi held onto their littlest one while Spencer checked his phone (presumably to read all the birthday texts he was receiving).
They were serving some tie dye realness, with Gunner looking super adorable in his multi-colored top and little blue shorts as his daddy proudly held onto him.
The former Hills star looked like he was enjoying his best birthday life as he playfully posed for a selfie while his friend laughed in the background.
Heidi enjoyed a similar experience with her husband of almost ten years, as they gleefully smiled at one another with Gunner in the middle.
Spencer's bros (who clearly did not get the tie dye memo) were also in attendance. What a day!
What are your thoughts on Spencer's birthday celebration? Sound off in the comments!