Greek islands vs Croatia for outdoor activities in June – swimming, snorkelling, exploring, hiking, cycling?

Hi all! I’ve seen some similarities between the Greek islands and Croatia for outdoor activities to do during our honeymoon next year. We are a very energetic couple and love to spend our days outdoors.

We would like to go somewhere authentic, not overrun with tourists (said everyone ever). We also are not into the nightclub scene and would prefer somewhere without the “tacky” feel to it.

Between Greece and Croatia would you have any recommendations? Pros and cons of both?

We are already going to the Italian coastline/Sicily/ almafi coast for a week beforehand 🙂