Who can most readily provide assistance to a diver in need?

The best source of immediate assistance for a diver in need is their buddy. The buddy system is a fundamental safety practice in scuba diving, where divers pair up to ensure they can look out for each other during a dive. This practice is in place because buddies are typically trained to recognize potential problems and provide help swiftly. They are physically present with the diver, allowing for quick communication and assistance if an emergency arises, such as equipment failure or a medical issue.

In contrast, while an instructor can provide guidance and training, they may not be present during every dive. Emergency personnel are typically located outside of the diving area and may take time to reach the diver in need. Other divers in the vicinity can offer assistance, but without the established bond and knowledge that comes with being a buddy, they may not respond as quickly or effectively as a designated buddy would. Therefore, the buddy is the most readily available and effective source of immediate support for a diver encountering difficulties underwater.