Outdoor retreat activities that are not team-building exercises

Trust falls and raft-building announce that you are doing team building, and adults respond to that announcement by performing enthusiasm rather than feeling it. The activity becomes something to get through.

The alternative is not "no activities". It is activities with a real purpose that happen to put people side by side.

Foraging, and then cooking what you found. Planting something that will still be there next year. Chopping and stacking wood for the fire you will sit at that evening. Building the fire itself. Clearing a path. Work with a visible result beats a metaphor for work every time.

Swimming in cold water. Walking a long way. Sitting outside in silence for twenty minutes. These are not exercises and should not be framed as any kind of lesson. They just reset people.

Someone will not want to do the cold water, and making participation the price of belonging is how you lose them for the rest of the retreat. Optional has to mean optional or it means nothing.