Can you add a map (GPS data) to a previously recorded activity that occurred in area w/o reception?

[weezer_beaver]

Went kayaking in a bay yesterday there was little no to zero reception on the beach we were at. Don't think there was any on the water. I didn't start the exercise log it was auto recorded by FitBit but it's there. Would be awesome if I could add the GPS data/map to it after the fact. I know this is a long shot but is this in any way possible?

[LZeeW]

Hello @weezer_beaver and welcome to the Community.  I'm sorry, but you need to use the GPS when you are doing the activity.  You don't say what model Fitbit you use.  Several newer models have an exercise shortcut called Outdoor Workout.  It is designed for things like kayaking and stand up paddle board.  If your Fitbit has built in GPS, then you can use the Outdoor Workout shortcut on your Exercise app.