Supporting distributed massive multiple-input multiple-output (DM-MIMO) in a distributed communications system (DCS) is disclosed. The DCS includes multiple remote units each configured to communicate downlink and uplink radio frequency (RF) communications signals with a number of user equipment (UEs) at different UE locations in the DCS. Each remote unit includes multiple antennas, multiple RF chains, and an RF switch circuit configured to dynamically couple the RF chains to a subset of antennas in accordance to the UE locations such that the subset of antennas can be activated to concurrently radiate the downlink RF communications signals and absorb the uplink RF communications signals. By dynamically activating the subset of antennas in accordance to the UE locations, it is possible to optimize signal strength and channel quality for each UE in the DCS, thus making it possible to improve wireless data capacity of the DCS with negligible additional hardware cost.