from MANILA:

We recommend booking a flight with Cebu Pacific. They offer 4 direct flights a day and are fairly cheap if you book in advance. You can also use Philippine Airlines.

by PLANE 
Cebu Pacific Airways: cebupacificair.com

Philippine Airways: philippineairlines.com

from CEBU:

You have 3 alternatives to get to Dumaguete...

by PLANE
Cebu Pacific Airways: cebupacificair.com

Philippine Airways: philippineairlines.com

by BUS
From the Cebu South Bus Terminal to Dumaguete:

Everyday, the yellow buses “Ceres” company offers 9 trips, from 6:00 to 18:00. Expect the trip to last 5 hours

by BOAT
From Cebu to Dumaguete Ferry Terminal:

Cokaliong Shipping Lines: cokaliongshipping.com

George & Peter Lines: GP Lines on Facebook

from BOHOL:

Two ferries per day are departing from Tagbilaran to Dumaguete...

by BOAT
Ocean Jet: oceanjet.net

from SIQUIJOR:

Two ferry harbours with Ocean Jet (Siqujor town and Larena)...

by BOAT
Ocean Jet: oceanjet.net