Recommended Items: Flippers, Hookshot, Bombs
Total Rupees: 150
Use an Ice Rod Clip on either side of the dungeon's entrance, slashing the sword to cancel Link's momentum after moving under the iceberg.
You should easily clip into the geometry and be able to walk into the dungeon's entrance. Flippers are not required.
This can be performed with or without Flippers. See also: Completing this dungeon without Flippers
There are a few crystal switches you are supposed to use the Boomerang to hit, but there are a few others way to do so.