I see on web site that there is a daily bus from Dubrovnik to Korcula, but on a map it appears as if Korcula is surrounded by water. Can you confirm the daily bus from Dubrovnik to Korcula?
Yes,Korcula is surrounded by water.
At the moment ( summer) daily bus goes at 9am and 3pm from Dubrovnik to Korcula.
Bus ride includes 15 minutes ferry crossing which bus takes to reach Korcula Island from mainland.
More info is here: https://www.korculainfo.com/bus/bus-dubrovnik-korcula.php