Oceanic flows of the very large scale associated with the general circulation often encounter planetary scale islands (e.g. Australia). The mid-ocean ridge system with segments separated by transform fault gaps present other examples of islands in the stream of planetary flow. A review will be given of the special dynamical features that arise when such geographical and topographic islands are considered. Both steady flows and time dependent, wave problems are examined.

In the steady flow case recirculations are generated by the presence of the island; the explanation for which follows directly from Kelvin's theorem and certain peculiar features of large scale oceanic flows as they are affected by the earth's rotation. Both the theory and confirming laboratory experiments will be described.

In the case of waves, interest is directed to the dynamics of large scale, westward propagating Rossby waves and the unexpected near-transparency of long meridional barriers to such waves as long as at least two small gaps are present in the barrier. Again, Kelvin's theorem is the essential ingredient for understanding the ability of the wave to pass through the barrier. The normal modes of ocean basins containing such barriers are described.