You can get to Patmos via ferry or plane to nearby islands and then take a boat from there.
There are ferries to Patmos from Piraeus, the main port of Athens.
Patmos is also connected by ferry with Leros, Lipsi, Kalymnos, Kos, and Rhodes islands. https://www.ferriesingreece.com/
Piraeus - Patmos
Access to the island of Patmos is achieved mainly through the ferry lines that connect the only commercial port of Patmos in Skala with Piraeus and the surrounding islands. From Piraeus (the port of Athens), there are several weekly ferries by Blue Star Ferries. The travelling time from Athens to Patmos takes about 8 hours. Tickets can be purchased from Blue Star Ferries headquarters or travel agencies. Ferries usually leave through gate E1 in the port of Piraeus (to Dodecanese). You can find information about the shipping schedule at www.bluestarferries.gr
During the summer months and usually starting from April - May (just before Easter), the company Dodekanisos Seaways operates daily services connecting Patmos with the following neighbouring islands: Symi, Kos, Rhodes, Kalymnos, Leros, Lipsi and Samos. Almost every travel agency is a point of sale. The duration of your trip varies depending on the island of departure. You find information about the shipping schedule at www.12ne.gr.
By Private Boat
In addition to the ferries, you can reach Patmos by private boat, overlooking the Aegean Sea. In some locations, such as the bay of Grikos, vessels can tie up to the pier, where supply services are provided.
From Athens Airport “El. Venizelos” by air. There is no airport o Patmos. The closest airport to Patmos is in Leros and Kos, Rodes, Samos, and Kalymnos islands. From there, a connection to Patmos by ferry.
You can also reach the island of Patmos using a private helicopter.