Tinos and Santorini sit at opposite ends of the classic Cyclades ferry corridor, and the direct boat between them is a handy way to go from one of the most devout and down-to-earth islands in Greece to the most famous one. Tinos is known for its pilgrimage church, its marble villages and its food; Santorini for the caldera, the sunsets and the crowds that come with them.
In this direction the crossing is a high-speed affair. Seajets and Golden Star Ferries run the direct boats, and even these fast craft need close to three hours or a little more. The quickest trip Ferryhopper lists from Tinos is 2 hr 50 min. Blue Star Ferries does link the two islands, but only from Santorini to Tinos, on a slow once-a-week sailing, so it is not an option for this direction.
Timing is the key thing to know. The direct service from Tinos runs only from June to October, and on 3 to 7 days a week within that window, so outside the summer you will need to change boats, typically at Piraeus, Mykonos or Paros. Fares on the direct high-speed boats started at €64.70 for one adult when we checked, with little difference between the two companies.
Before booking, think about the Santorini end. Every boat arrives at Athinios, the island's main port under the caldera cliffs, and afternoon arrivals often coincide with several other ships. Arrange your transfer before you leave Tinos, and book accommodation on Santorini well in advance for summer and Easter.