From the small beach next to the ferry port it is possible to walk round to the Venetian lighthouse on the north side; on the way you will pass the ruins of a Basilica from the Byzantine era (6th Century AD) and the more modern lighthouse. The walk is no more than 900m each way and for sure footed people should take no more than 10-15 minutes.
You can combine this walk with a trip to Emblisi beach where you can buy refreshments from the kiosk. It’s always wise to carry some liquids with you just in case the kiosk is closed.