We were able to reserve a day trip to the Blue and Green Caves by shopping around the day before. Several companies offer various excursions from Hvar, it just depends on how much time you have and what you are interested in seeing. We left the port of Hvar around 9:30am with a return time of around 6pm.
We woke up early this morning to catch the ferry from Split to Hvar, which was about a two-hour trip. We chose to utilize the ferry for the majority of our adventure around Croatia, but many have also rented cars without any issues.