Submersible Pumps are meant to be at the deepest part inside of your pond. They can be placed directly in the pond, inside your skimmer, or a pond vault box. Most submersible pumps are meant for smaller ponds ranging in 50-5,000 gallons per hour of circulation. Some submersible pumps like the ShinMaywa Pump or the OASE Profimax pump (pictured below) can also be used to drain your pond when needed.
*Disclaimer: submersible pumps are not meant for swimming use, for safety reasons swimming pools/ponds you need an above-ground/in-line pump.*