The inner port and the city center are best explored on foot, but there are other types of transport. From a horse-drawn carriage to a double-decker bus, find the transport you prefer. The buses are good, biking is pretty easy all year round (as long as you don't mind getting wet) and the taxis are really good. It's a small city and you definitely don't need a car here.
Although of course it's easier if you have one).