It's safe as long as you're experienced and don't panic on narrow winding roads with cars whizzing by in both directions.

We have never hired a scooter in Greece but spoke to a doctor at the hospital on Santorini on our last visit and he said they have a lot of tourists brought in who have had accidents coming off their hired scooters. He thought it was due mainly to inexperience.

The hospital was very basic, not the sort of place you'd want to end up in for anything serious.

Kay

I agree with both posters -- it is safe to ride in both locations provided you're an experienced scooter rider. Too many times we've seen tourists bandaged up (or worse) from accidents.
Have a great (and safe!) trip!

Having spent many months on the islands, i have seen terrible accidents happening from inexperienced people who only rented scooters to save on money.
One more thing everyone seems to ignore or not to take seriously.
In Greece you cannot just drive a scooter without a special approval on your driver's license.
That means that you will be driving illegally if something should happen.
Business owners will never tell you this.

The other problem that I see is that in the hot summer months few riders are dressed in more than tee shirt and shorts. Even a minor tumble could result in a bad case of road rash, spoiling your holiday. Would you be prepared to wear proper protective clothing, which would be very hot? I would rather ride around in comfort, in a car with a/c.

Forgot to mention that Santorini has no Hospital, but a so called Health Centre, which offers only 1st grade services.
In most cases patients will have to go to the Hospitals of Naxos or Syros.