Field trials using a man-portable, commercially available, electromagnetic induction (EMI) sounding instrument, with a plug-in data processing module for the remote measurement of sea ice thickness, are discussed. The processing module was made to allow for the direct determination of sea ice thickness and to show the result in a numerical display. The processing module system was capable of estimating ice thickness within 10 percent of the true value for ice from about 0.7 to 3.5 m thick, the thickest of undeformed ice in our study area. However, since seawater under the Arctic pack ice has a relatively uniform conductivity (2.55 + or - 0.05 S/m), a simplified method can be used for estimating sea ice thickness using just an EMI instrument. This technique uses only the EMI conductivity measurement, is easy to put into use, and does not rely on theoretically derived look-up tables or phasor diagrams, which may not be accurate for the conditions of the area.