Walking on a glacier is a very fun experience. You can choose from a short hike or a half day hike. Local Guide is the original company with the best guides. They are all from the area and provides the best service. Here are their glacier hike tours:
Glacier Discovery (4 hours) : go higher up on the glacier to a beautiful icefall, best for those looking for an in-depth glacier experience in Iceland, perfect for those who enjoy long hikes, or just looking for a bit of an adventure.
Glacier Encounter (2.5 to 3 hours): classic short tour and the perfect introduction to glaciers in Vatnajökull National park.
Both tours are available from April - September, and meet at the gas station near Skaftafell National Park