This paper presents a comparison among two types of linear generators for wave energy conversion: an inner-permanent-magnet-slotted-tubular-linear-generator (IPM-STLG) and an outer-permanent-magnet-slotless-tubular-linear-generator (OPM-STLG). The magnetic and electric quantities are extracted and evaluated using Finite Element Method Magnetics (FEMM) software and Matlab. These quantities include magnetic flux, cogging forces and end effects, inductances, currents, e.m.f., and power. In addition, a comparison of the two topologies and the different parameters has been performed. The aim of this work is to show a methodology to design Tubular linear generators for Sea Wave energy production, together with a comparison among different architectures.