Is "to stay happy" correct?

Hi,
Remain (in a state of happiness).

Continue (to be happy).

Clive

Thank you!
Is it commonly used? I searched for it but Google didn't return many results.

It's grammatically okay, but what does it mean? A persistent state of happiness doesn't exist for most people forever.

Perhaps something like this: I was afraid the baby would cry while we were visiting our friends, but fortunately, he stayed happy throughout the visit.

The context would be like this:
You traveled somewhere, during this journey you stayed so happy. Does that work?
Thanks!

It's just not very natural.

I was so happy throughout the entire journey.

I was in this lovely, persistent state of happiness the whole time I was there.

Thanks a lot

Would a translation using "stayed this happy" rather than "stayed so happy" work better for you, GG? Maybe something along the lines of: "I'm happy now, and since I intend to stay this happy, I am not going to be spending Christmas with my mother-in-law?"

For some reason "Stay happy!" jumped into my head as a cheesy parting line, along the same lines as "Be lucky!", "Mind how you go, now

I like my mother-in-law, but what you've written seems okay to my ears otherwise.
"I stayed so happy the whole time" just doesn't ring natural.
Don't worry -- stay happy!

which is correct

stay happy

stays happy