Answer:
Here's the corrected sentence with the appropriate punctuation:
"There are three cities I would like to visit - Oslo, Norway; Sydney, Australia; and Cardiff, Wales. However, I have yet to travel to any of them."
I added dashes to separate the list of cities from the main sentence, and used semicolons to separate the individual items in the list. I also added a period after "Wales" to end the sentence before starting a new one with "However."