I can (road) bike with an Airpod fairly securely in. For longer rides where I want to listen to a podcast, a little bit of surgical tape brings even more security.

You may be aware of this, but the recommended way to wear Airpods (especially the 3rd gen non-Pro?) is to twist the stalks towards your face to 'lock' them into place better.

(I discovered this when I was about to angrily throw out my new 3rd gen Airpods, as they were fatter than my original gen 1 model, and just wouldn't stay in place. I've never seen anyone else doing this [and I sometimes get comments from people for wearing mine oddly] but it's a game-changer.)

https://www.reddit.com/r/airpods/comments/qgqo5a/psa_if_the_...

I use them all of the time during my biking and workouts. I even sleep with them quite often. Never fall out somehow.

It's very dependant on your ears and the eartip size you use. I personally would not bike with them, because as good as the passthrough audio is, there could be small differences in localizing sound that could really cause trouble on a bike. The passthrough is great, but not life or death situation great.

Edit: this is for the Pros. The open non-pros seem like they would be safe for biking at lower volumes.

I bike with them, and while they fit me fine, the wind noise is a bigger issue. Shokz[0] are probably better for biking speficially, but AirPods work fine if you just pause your podcast on the descents.

[0]: https://shokz.com/

They are pretty snug without hurting. I sometimes even fall asleep with them and they stay put most of the time. Mine are the regular cheaper air pods. Not the pro or whatever they call it.