A fluid containment system for a riser slip joint includes a fluid container sealingly engaged to a fixed part of the slip joint. A movable part of the slip joint is axially movably engaged with the fixed part. An annular seal is disposed between the fixed part and the movable part. A body of fluid disposed in the fluid container has a level selected to submerge the annular seal and at least a portion of the movable part. The system includes means for maintaining a level of the body of fluid substantially constant.