 If you've a boat and plenty of time to explore Ibiza's 170 km (105 miles) of coastline, so much the better.
The coastline is one of the biggest in the area to explore.
mnli hypothesis: The coastline is one of the biggest in the area to explore. premise:  If you've a boat and plenty of time to explore Ibiza's 170 km (105 miles) of coastline, so much the better.