There's no way to do this in GC afaik, but it sounds useful so I adapted a script to delete all GC connections.
You need a Windows PC, Mac or Linux.
1) Get Python 3.
https://www.python.org/downloads/
2) Download this file: pastebin.com/.../DjZw6zW2
(If that link doesn't work, go here and click Download: https://pastebin.com/DjZw6zW2)
It's a script called gcunfriend.py.
3) Windows: Double click on gcunfriend.py
Mac OS: Run gcunfriend.py in Terminal. For example, assuming you downloaded the script to your Downloads folder:
- Open the Terminal app.
- Type:
cd ~/Downloads
python3 gcunfriend.py
4) You will be prompted for your GC name and password, and to confirm you want to delete all your connections.
Credit goes to Kyle Krafka and Michael Payne for the original script: https://github.com/kjkjava/garmin-connect-export/
EDIT (June 25, 2019): Linked to new script -- the old script didn't work anymore because Garmin Connect changed the way you log in.
DominicM I've updated the script so it works again, after Garmin Connect changed some things in the login process. Go here and click Download:
WillNorthYork, thank you, you are a machine! Script is busy deleting over 700 connections as we speak. Thanks a ton!
Can you update this post again so it works?