If you do not have a car available and you do not want to walk ( Volos is a city suitable for walking ) you can take a bus. For bus info visit Volos Municipal KTEL
Νο 1 is the most important line ... here
Νο 5 takes you to the beach ... here
Νο 6 does that as well ... here
For further out use Volos Intercity KTEL
Take a look at these destinations :
For a Pelion excursion you can even take a train ... see here
