What can the third umpire check without a player asking?

Under an Umpire Review, the on-field umpire may refer or consult the third umpire about:

• Run outs, stumpings, bowled and hit wicket appeals (the umpire refers by making a TV screen shape with their hands).
• Caught and obstructing the field decisions, after the on-field umpires have consulted each other.
• Boundaries: whether a four or six was scored, whether a fielder touched the ball while in contact with the boundary, and the runs from an overthrow or wilful act. If the evidence is inconclusive, no boundary is awarded.
• Batters running to the same end, when the umpires are unsure who made their ground first.
• Contact with a camera or its cables above the playing area.
• No balls after a dismissal, if the bowler's end umpire is unsure about the fairness of the delivery.

The third umpire also automatically reviews any call of Short run, and reviews television replays of the bowler's feet landing, advising the bowler's end umpire to call No ball if the front-foot or back-foot requirements are not met.

Source: ICC Men's Test Match Playing Conditions (effective from October 2026), Appendix D, paragraph 2 and clause 21.5.