There are many things to see and do in the Dikaios area.
Nature lovers will certainly appreciate this part of the island. The imposing Dikaios Mountains are full of wooded areas which you can go and explore along with the cute little traditional villages that abound in the area. You can hike out of Zia and reach the Christos Church on the top of Mount Dikaios. An all time classic. The Tigaki Salt Lake and the Marmari area in general, being a Natura area, is simply amazing in its biodiversity. Nature has remained untarnished and pure while the presence of the majestic flamingoes along with a large variety of migratory and local birds makes the area all the more attractive.
There are also a number of monuments of note to be found in the area such as Harmilos’ grave, the Pyli spring, the Kapama and Aghios Pavlos Basilicas, the Voukolies stables but they are overall quite scattered. The Old Pyli settlement and fortress should be your focus in the area in terms of monuments, a significant religious center during the Byzantine period with beautiful murals adorning the walls of some of its Churches
Sandy beaches can be found in Tigaki and Marmari but they are often quite crowded as they are relatively close to Kos Town. There are usually plenty of waves as the Northern part of the island is usually harassed by winds during the summer. Marmari is an ideal place to kite as the winds are usually strongest there when the North wind blows.
So overall there are plenty of things to see and do in the Dikaios area with a lot of focus on Nature and the elements.