I created a simple Java application to convert my old Suunto D3 dive logs for import into Garmin Connect. It's pretty limited but seems to work so I'm sharing it as open source for others to try. It might also work for converting dive logs from other Suunto computers but I didn't have anything else to test with besides the D3.
https://github.com/nradov/SdeToFit
Hopefully this can be useful for some of you. If you find a serious defect then I'll try to fix it but I can't promise any real support.