Offshore infrastructure is extremely costly to design and build. Advanced and scientifically sound testing programmes can yield substantial savings to overall infrastructure costs due to the improved reliability that results from better and more accurate characterization of offshore sediments. Well-designed and carefully executed laboratory tests are paramount to the successful design and construction of offshore infrastructure. A variety of laboratory tests are available to the 21st century engineer to characterize the physical properties and mechanical response of offshore sediments and derive design parameters for offshore geomechanics analyses. To be competitive, engineers must be equally familiar with cutting-edge testing tools as well as conventional methods used in practice for decades. The most common and relevant laboratory tests available to assess fundamental aspects related to the composition and mechanical behavior of offshore sediments are discussed. These include basic characterization, soil fabric analyses and mechanical tests. Particular emphasis is placed on the underlying background and rationale associated with each test discussed.