At sea, the oldest hand signal to indicate distress is to flap the arms up and down. Cloth or bright objects may be held to increase visibility.^[1]

In aviation, a downed pilot would hold their hands straight above their head to indicate that they want to be picked up. If they need help repairing their aircraft, they would hold their arms out straight to the side.^[2] One method of signalling an emergency to a rescue helicopter is to raise one's arms in a "Y" shape, indicating that "yes", rescue is needed. (Conversely, one arm raised and one lowered signifies an "N" for "no".)^[3]

During the COVID-19 pandemic, there were extensive lockdowns which kept people at home. As people then mainly communicated by social media, the Canadian Women's Foundation (CWF) devised a hand signal called the Signal for Help which women could use to secretly indicate that they were at risk of domestic violence and so needed assistance. Knowledge of this signal then spread through social media such as TikTok. In 2021, a girl in Kentucky then used the signal when she had been kidnapped and people who saw it alerted the local police who rescued her.^[4][5]

The CWF signal has the palm outward with the thumb across it.^[6] The fingers are then closed over the thumb to symbolise that one is being held or hurt.

In Guyana in 2022, the Ministry of Human Services and Social Security announced a gesture of clasping the fingers into the palm and releasing them, in a repeated motion three times, to be used as a signal that the person was a victim of human trafficking and required help.^[7]