Date: 202003
Local time of day: 1801-2400
Location: ZZZ.Airport, US
Flight conditions: VMC
Weather elements / visibility: 10
Light: Dusk
Aircraft: Small Transport; Low Wing; 2 Turbojet Eng
Operator: Corporate
Operating under: Part 91
Flight plan: IFR
Mission: Ferry / Re-Positioning
Flight phase: Final Approach
Airspace: Class B ZZZ
ATC / advisory: Tower ZZZ
Reporter function: Pilot Flying; First Officer
Reporter qualification: Flight Crew Multiengine; Flight Crew Instrument; Flight Crew Commercial
Human factors: Situational Awareness
Second reporter function: Pilot Not Flying; Captain
Anomaly: ATC Issue All Types; Airspace Violation All Types; Deviation / Discrepancy - Procedural Landing Without Clearance; Ground Incursion Runway
Detector: Person Flight Crew
When detected: Taxi
Result: Air Traffic Control Provided Assistance; Flight Crew Requested ATC Assistance / Clarification; Flight Crew Returned To Clearance
Contributing factors: Environment - Non Weather Related; Human Factors
Primary problem: Human Factors

Narrative: Roughly 10-12 miles from Runway X; ZZZ Approach directed us to switch to the tower frequency after clearing us for a visual approach. The Pilot not Flying; my Captain; switched the pre-dialed in frequency for the Tower and called. I do not remember hearing a response as we continued our pre-landing checklist.As Pilot Flying I was focusing on hand-flying the precision approach and responding to this pre-landing checklist. Due to the recent slowdown in flying; I felt it prudent that I hand-fly this precision approach to keep my skills up. All of my attention was on the flying.In the past month I have flown less than 15 hours and then only very sporadically. The last day of flying prior to today was over two weeks ago and was with the same Captain.The landing was uneventful and as we were exiting the runway; the Pilot Not Flying called 'Clear of Runway X at taxiway.' We did not hear a response. Pilot Not Flying tried again; and it was at this moment I realized that we were not on the correct Tower frequency and dialed in the correct frequency.Pilot Not Flying had mistakenly dialed in ZZZ1 Tower Frequency instead of ZZZ Frequency. We realized that we had landed without a landing clearance. We promptly contacted the tower and admitted our mistake.I believe the contributing factors in this event were lack of recent flying + landing at night after a long day and a long flight.Corrective actions for this would be to pay closer attention to radio calls by Pilot Not Flying while acting as Pilot Flying and to ensure that we are given proper landing clearance before commencing landing. It is especially important to be extra vigilant when you are not as current as you are normally.


Second narrative: We were switched over to ZZZ Tower; but I inadvertently switched to frequency; which is ZZZ1; one of our previous stops that day. I checked in; and did not immediately get a response; so I continued with the checklist. We completed the checklist and did what we have done hundreds of times before landed. I called the tower to see if we could take Runway X for taxi; and of course; got no response. I called a second time; which was when my First Officer noticed that we were on the wrong frequency. We switched in; and the Tower asked us if we had heard them. We admitted our mistake and continued on.The takeaway is you can't let even an important thing like the checklist distract you from completing all of the required tasks in front of you. A contributing factor is that this was my third flight in over a month because of a massive slowdown in activity due to the Coronavirus pandemic. Lesson 2 is you have to be especially vigilant when you aren't as current as you normally are.


Synopsis: Flight crew reported landing without clearance due to fatigue and lack of recent flying assignments due to COVID-19-related decrease in flights.