All the location info (pins, notes, etc) are stored locally. Offline functionality isn't explicitly supported for the map itself but the default behaviour of the system is to cache quite a lot of map-tile information. As long as before you go offline you "inspect" the areas of the map you want to use you should be fine. I've used it offline a few times myself and it works reasonably well. I'd say the feasibility depends on whether you're walking around a city (small map areas) vs going on a road trip (huge map areas). Hope that helps!

Hi Lukas! My goal was to design an app that really excelled at this specific use case in terms of UX. I've used Google My Maps but I found it more of a desktop power tool, rather than a simple, fast, mobile-first kind of experience. To me, on iOS, My Maps feels shoehorned into the flagship Google Maps app.

If you try Relay I think you'll be surprised at how much better the whole experience is! I spent a long time designing and optimizing the UI ;)