I wrote a program to convert Suunto dive logs. See more details in this post.
I think Garmin should add a way to import dive log files (csv, zxu, dl7, text, dlg….) when you buy a dive computer from oceanic, Suunto… you can download and use their soft where. logging dives is drilled in to the new diver’s head as a most do thing. so, when you can't keep your log book all in one place and nice and clean I feel that some people may use it as a point to not get this computer.
My MK1 has finally arrived. Is there a step by step for transfer Suunto DM5 to Garmin Connect? Doesn't seem like there's a thread for this specifically yet?
Try exporting an MK1 dive as a .fit file. Then export a movescount dive as a .fit file. These files are just XML files (possibly zipped), and there might be some subtle differences that make the movescount file not importable into connect. You might have to edit that file in a text editor, matching the fields in the MK1 file.