A base for a modular shipping container is provided. The base includes a base frame having a first end rail, a second end rail, a first side rail, and a second side rail. The first end rail is attached to first ends of the first side rail and the second side rail, and the second end rail is attached to second ends of the first side rail and the second side rail to form a periphery of the base. The base further includes a pair of fork tunnel assemblies removably coupled to the first side rail and the second side rail and extending therebetween. The pair of fork tunnel assemblies are spaced along the base frame to define a fork pocket distance therebetween. The fork pocket distance defined between the pair of fork tunnel assemblies is configurable between a first fork pocket distance and a second fork pocket distance.