An excellent location along the coast that gets few visits from birders. April-May seems to be the best season for spring migration. Nice birds you can encounter here are Greater Flamingo, White-winged Tern, Kentish Plover and Collared Flycatcher. Check the ebird hotspot at https://ebird.org/hotspot/L1807623 .
Take the small beach road about 800 m north of Gialova (to the Erodios camping). Check the bird hides and bushes along the road near the beach. Check the beach. After about 3 km you have acces to the lagoon to the north (park your car here, there is a barrier). Walk counter-clockwise along the northern lagoon, and after about 1.2 km you arrive at an observation tower which has the best sights on the fresh water lagoons. You can walk around the lagoon (6-7 km) passing the Voidokila beach. Just past the Voidokila beach the trail is difficult. Alternatively you can also drive a few km to the Voidokila beach and park there. Near the beach there are also some excellent mudflads and some dunes.