A drilling rig transfer system includes a mobile transfer beam, a trolley assembly operatively attached to and moveable along the mobile transfer beam, and a connection mechanism suspended from the trolley assembly for connecting to and lifting a device. The mobile transfer beam is suspended from first and second traveling blocks through connections at first and second suspension positions along the mobile transfer beam. A method of transferring a device may include suspending a connection mechanism from the trolley assembly over a first location, lowering and attaching the connection mechanism to a device disposed at the first location, lifting the device with the connection mechanism, moving the trolley assembly along the mobile transfer beam to position the connection mechanism and the device over a second location, and lowering the connection mechanism and the device into the second location.