If you are looking for a walkthrough for a different "Lost Lagoon," it might be one of these:
Once on the boat, use your pole or sword to activate the . This lowers a bridge of vines to the east. lost lagoon walkthrough
Swimming is allowed and incredible—the water stays cool even in July. The deepest point is about 12 feet near the far cliff. No lifeguards, so use the rope swing at your own risk. If you are looking for a walkthrough for