At its core, teamwork is when a player coordinates with one or more other players in a pre-determined manner to obtain a desired outcome.
As with other team sports, underwater hockey has many different coordinated maneuvers to choose from for a given situation. Devoting resources (players) to a desired outcome is always a balancing act between too many and not enough players engaged in the play. Too many players involved in the play may leave the team unable to react to a change in direction, not enough players and the goal may not be achieved.
Underwater hockey has additional challenges of breath control and needing to leave the play to surface. If too many players are involved in the play at a given time, and they all surface simultaneously, there may not be anyone down to stop a play by the opposing team. This can be true for both offensive and defensive situations.
Another major challenge in underwater hockey is that players can not communicate verbally during the game, so strategies must be understood ahead of time.