Small Aircraft
Flight Crew Instrument
Flight Crew Last 90 Days 2.5; Flight Crew Total 3490; Flight Crew Type 2500
Situational Awareness; Communication Breakdown
ATC Issue All Types; Deviation / Discrepancy - Procedural Clearance; Deviation / Discrepancy - Procedural Published Material / Policy
Flight Crew Landed As Precaution
Environment - Non Weather Related; Human Factors
Aircraft X was on an IFR flight from ZZZ to ZZZ1 at 4;000 feet. Was flying the GPS XXR approach into ZZZ1.  Approach at XYZ.X cleared me for the approach into ZZZ1 and to contact Tower.  Approach did not give me the Tower frequency and I looked up the frequency on the approach plate and mistook the UNICOM frequency of XYY.AB and broadcasted my position and intentions.  I thought it was odd that I did not hear any response; but with COVID-19 conditions I was not sure and continued to broadcast to short final and landed.  I taxied back for an IFR flight back to ZZZ2 when a pickup truck pulled up beside my plane.  I used ground XYX.C to find out my deviation and followed the truck to park and call Tower.  I realize now that the correct Tower frequency is XYD.X.I picked up an IFR flight plan back to ZZZ2 without incident and flew the GPS XY approach into ZZZ2 to a full stop.
Pilot reported being on the incorrect frequency and thinking it was odd that no other aircraft were heard while landing.