We live one block from the ocean in North Carolina. We have had our fig tree for about 15 years and have had bumper crops until last year. The fruit matures to approximately three-quarter size and does not ripen. We fertilize and water the tree.
Fig Tree Fruit Not Maturing
Certified GKH Gardening Expert
The only thing I can think of is poor pollination. If there is a lack of pollination, the fig fruit will remain very small and may also drop. You could try adding some bright-colored flowers close by to entice bees, but make sure they are tolerant of your seaside location.