A total of 110 first-year sea ice samples from Prudhoe Bay, Alaska, were tested in unconfined and confined constant strain rate compression. All of the tests were performed in the laboratory on a closed-loop electrohydraulic testing machine at −10°C. The confined tests were performed in a conventional triaxial cell (σ1 >σ2 =σ3 ) that maintained a constant ratio between the radial and axial stress (σ2 /(σ1 )=constant) to simulate true loading conditions. Three strain rates (10−2 , 10−3 , and 10−5 /s) and three σ2 /σ1 ratios (0.25, 0.50, and 0.75) were investigated. This paper summarizes the field sampling and testing techniques and presents data on the effect of confinement on the compressive strength, initial tangent modulus, and failure strain of the ice.