• English / United States: Old Man Swamp
• Japanese / Japan: ヌマタ老人
• Japanese (Romanized) / Japan: Numata rōjin
• Japanese (TL) / Japan: Old Man Numata

Old Man Swamp runs a Mudkip preserve. Ash and his friends first met him just after the baby Mudkip was rescued. He got mad at the group because he thought they were disturbing the Mudkip. He quickly changed his attitude after they told him they rescued the baby Mudkip.

He invited them to his house and he showed him the Mudkip eggs that he was watching. He explained to Ash and company that he was looking to find a trainer who can take care of the older wild Mudkip. Later after watching one of the Mudkip eggs hatch, Old Man Swamp heard one of his alarms go off and quickly went to find out what the problem was. Finding out that Team Rocket was causing problems and that they wanted to capture the Mudkips, he was not happy.

After rescuing the baby Mudkip's from Team Rocket, Old Man Swamp noticed how well the older Mudkip got along with Brock and he suggested that it should journey with Brock.