The continuing growth in demand for hydrocarbons has led to the increase in the stage count of hydraulic fracturing in unconventional reservoirs. A typical stimulation method is the plug-and-perf system, which uses frac plugs for zone isolation. Conventional plug-and-perf requires milling out to recover the flow path for hydrocarbons after fracturing is complete. Fully degradable frac plugs are in great demand to eliminate milling out, reducing the cost and risk of well completion, and extending the lateral length of wellbores. A key material for fully degradable frac plugs is a sufficiently degradable rubber with good sealing properties for the sealing elements of the plugs. This paper provides an overview of the material properties of the degradable rubbers that were developed by a comprehensive study of materials, and their suitability as sealing elements for degradable frac plugs. Nonlinear, three-dimensional multi-body contact analysis and qualification testing were integrated to design and test the sealing elements. The results indicate that the resulting sealing element will function at over 100 MPa without failing.