We think April, May and October are the nicest months to visit. In spring the wildflowers are sensational, it’s not too hot to explore its many well-marked footpaths, beaches and off-shore islands, and the summer holiday-makers haven’t yet arrived (not that there are many on Alonissos). August is the busiest month, with a small influx of Greeks. Late September and October are perfect for swimming, as the sea is still beautifully warm and there are very few people around - sometimes you feel as if you have the island almost to yourself.
There is no airport on Alonissos. To get there you need to travel by ferry from the nearest airports, which are on Skiathos (2.5 hrs by ferry) or at mainland Volos (3-4.5 hours by ferry). You can also fly to Athens or Thessaloniki and continue via internal flight or ferry.