From Caye Caulker you need to catch the ferry back into Belize city. The Ocean Ferry is a few dollars cheaper than the express so if you’re on a tight budget you should definitely go back with the Ocean Ferry. Once you’ve bought your ticket, if your luggage is large you’ll need to check it in with the ferry to collect once you disembark. You’ll also need to be sure you personally check in roughly 20 minutes before boarding. When you arrive in Belize city you can either take a taxi to the bus station or you can simply walk. It’s an easy 10-15 minute walk depending on how fast you walk and what shape you’re in.
To get to the bus station from the port: once you’ve collected your luggage and you exit the ferry, immediately make a left onto the street and keep walking until you come to a large bridge called Swing Bridge on your left. You’re going to cross the bridge. Once you get over the bridge you’re going to come to a three way street with two options to your left and one to your right. Make a left onto the second street (the one farther from the bridge than the first, aka Albert street) and walk along that street until you get to King street (you should be able to easily see the sign for this one but if not, it’s the 4th cross street you’ll come to. At King street you’re going to make a right and keep walking straight until you cross another, smaller bridge. On the other side of this bridge, slightly to your right is the bus station you’ll need to take to get to San Ignacio. Ask around to the local vendors to see which bus you need to get on. Don’t worry about the ticket, you simply pay on the bus (9 BZD or $4.5 USD). Once you’re on the bus, just relax and you’ll be in San Ignacio in roughly 2.5 hours.