We split from my brother-in-law in Split. He will have joined us for part of our trip that overlapped with his own. We will have been staying out near Zinjan beach. His flight onward did not coincide with our plans, so he is in Split an extra day and night after we split. I want him to be able to make good use of his day (having already spent part of one day, plus a full day in Split, But because his flight leaves pretty early the next day, he probably cannot overnight on one of the islands. But is there a ferry or water taxi or some day trip somewhere? Also, where is a good accommodation choice for him that last night? Thanks.
He could do a day trip to Hvar or Brac, see schedules on the Krilo and Jadrolinija websites.
I suggest using Booking.com for hotel search. He can also stay in Trogir, which is close to the airport and a cute little place.
Trogir is an excellent choice to stay especially with an early flight as it is very close to Split airport, and is accessible by public transit if you don't want to call a taxi. I prefer it to Split. It's best to stay in or near Trogir if you don't have a car and not on Čiovo. There are also ferries from Trogir to islands such as Drvenik Veli but I'm not very familiar with the sailing schedule. If he is going from Split also check TP Lines for ferry schedules.
I agree with valadelphia about visiting Hvar as a daytrip from Split. We did exactly that, and it was wonderful and easy. I can't speak to Brac since we didn't visit. However, I would choose the island with the easiest and most convenient ferry/catamaran schedule since he has an early morning flight the next day.
Several people recommend day trips to Hvar. What would one do there for the whole day?
Why do you ask?