Subtidal sea level fluctuations in the Sea of Marmara, their interactions with neighbouring seas (Black Sea and Aegean) and relations to wind forcing were examined over a three-year (1992-1994) period. Although the dominant sea level fluctuations occurred at time scales greater than 10 days, there are shorter period fluctuations occurring between 3-8 days. Subtidal sea levels for Sea of Marmara are highly coherent for all subtidal frequencies. There is no cross coherency for periods greater than 2.5 days between Sea of Marmara and Black Sea, while there are same coherent fluctuations in subtidal band between Sea of Marmara and the Aegean Sea. Local wind forcing is important for the Sea of Marmara and most of the sea level change is driven by NE-SW wind for Erdek and Fenerbahce. However, at longer time scales, nonlocal contribution is important.