This book introduces details of inspection criteria and inspection techniques, which are widely recognized by the marine construction industry as a reliable means of inspection of structure members and their welds during the construction of surface vessels and other related marine and offshore structures. This text incorporates the criteria for phased array ultrasonic testing (PAUT). Since 2016, PAUT has become a common non-destructive testing method in use in shipyards for marine and offshore structures across the world, as it provides quicker examination than conventional UT technique for complex geometries. Moreover, this book includes guidance for time-of-flight diffraction (TOFD) ultrasonic inspection. The TOFD ultrasonic examination technique provides improved detection and sizing capabilities of discontinuities compared to standard ultrasonic pulse-echo techniques. Both PAUT and TOFD produce a permanent record of the inspection in electronic format.