Once you have arrived at McCarran International Airport and gone through the security checkpoints, it is very easy to get around and between terminals. Terminals are within walking distance. However, there are a few options that you can try to move between terminals and gates.
Inside the secure area for ticketed passengers most comfortable way to get between terminals and gates would be McCarran Airport Tram, which operates on three colored lines. Green line trams operate from Terminal 1 to C gates and back; Blue Line trams operate from D gates to Terminal 1 and back; And Red Line trams operate from Terminal 3 to D gates and back.
There is an Airport Shuttle Service that operates for passengers between two terminals, and they are available every 15-20 minutes, however, keep in mind that these buses are outside of the secure area, which means that you will need to clear security checkpoints once again in your terminal to get to your flight. The bus stop in Terminal 1 is on Level Zero across the pedestrian walk and for Terminal 3 on Level Zero in the center curb area.
It is also possible to walk between Terminal 1’s A, B, and C gates as they are connected via pedestrian walkways inside the secure area. However, it is not possible to reach Terminal 3 on foot. Keep that in mind to get to your flight on time.