During the summer of 1983 and the spring and summer of 1984, the authors conducted side scan sonar and shallow subbottom surveys in conjunction with bathymetric and diving surveys along three northern California coastal structures to determine the condition of the structures before extensive damage occurred. Then the applicability of the data collection techniques for condition surveys in general was evaluated. Two of the structures surveyed are the parallel jetties that protect the entrance to Humboldt Bay, California, and the third structure is the outer breakwater at Crescent City, California. It was found that the side scan sonar is an excellent tool for defining the toe of the structure; also, when waves are low, it can be useful in determining armor types and the slope of structures. The subbottom system provided information on fault and bedrock locations; however, other systems need to be tested to see if any of them can locate buried armor near the structures.