Wading through water is harder than walking in air because water is denser than air and creates resistance to your movement. Divers move slowly, steadily, and deliberately to conserve energy and, therefore, gas.
Streamline yourself, keep level, and keep your equipment hoses and gadgets tucked close to your body. Do not overweight yourself because this increases your drag. Your instructor will teach you how to achieve proper weighting during your confined water sessions. Fast swimming causes you to get tired quickly, so relax and take it easy. Moving slowly allows you time to observe what is in your surroundings so that you can really enjoy your dive.
Currents are rarely uniform and usually stronger at the surface and around points of land and narrow passes. Swim across the current, or go to the bottom as soon as possible, making sure you don’t exceed your maximum depth.