Takamatsu - Transfer time ferry to train

Will arrive at at Takamatsu port from Naoshima and would like to catch a train from the JR station nearby. Train leaves 15 minutes after scheduled arrival of ferry.

Is that enough time to safely make the transfer, including a pickup of luggage from the lockers at the station?

15 min seems to be stretching your luck. Itfs 6 min walk per google maps, but google maps walking times in Japan arenft realistic. They donft account for a red traffic light, for you looking around a sec, for crowds.
You still need to get off the ferry, find your way, collect your bags, find the platform, get up or down some stairs...
You might be lucky and make it, but itfs very tight and relies on your ferry not having even a minute of delay.

Enjoy your trip to Shikoku!

Once you get to Takamatsu Station, it's easy to navigate. Last time I was in Takamatsu I was trying to find the shopping street with Google maps' help and managed to get completely turned around and walked in the wrong direction for about 15 minutes.

You could make it if you don't get turned around, Takamatsu is flat and is nice to walk around, it's the getting turned around that is the only issue.

Good luck!