There are many dynamic events responsible for the production of a multilayer surface foam in seawater. The residence time of foam at the surface depends on the stability of the bubbles in that foam. This paper examines the stability of three-dimensional foam layers of various thicknesses produced by blowing air through controlled laboratory samples of seawater and a sample of seawater obtained from an Atlantic coastal site. The results clearly show that for oceanographically relevant salt concentrations between 20 and 36 parts per thousand there are no appreciable changes in the foaming characteristics of seawater due to salinity variations. The stability characteristics of real seawater closely followed those of the simulated seawater. Procedures and equations for estimating thickness variations and lifetimes of foam layers on a saltwater surface are contained in this paper. The results also provide some valuable insights into the influence of organic surface active materials that have been scavenged to the surface by rising bubbles and removed by the bursting process near the surface of a three-dimensional foam layer. ¿ American Geophysical Union 1988