Coming Dec 18th

Hi all,

I'm flying in with my husband and son (15 yrs) Dec 18th on an overnight flight. So technically arriving early Dec. 19th. We have a couple excursions planned on the 20th and 22nd, but should I have something planned for the afternoon of the 19th?

We want to stay awake as much as possible but I wasn't sure how difficult it was to jump into a tour last minute. I was thinking Hvammsvík or Sky Lagoon might be good, but again I don't know if I should wait or schedule something now.

Should we be more active to stay awake?

Thanks in advance for any thoughts or ideas.