Year 2000 (MM) was a leap year of the Gregorian calendar that started on a Saturday. It was a century leap year. In some countries such as the UK, they claim it as the 3rd millennium, but the US denied this until 2001. After Mermaid Man and Barnacle Boy II and Hooky premiered on April 8, 2000, no new episodes aired until October. This also happened in 2004. This will be the second and last time there were episodes in December until 2012, when It's a SpongeBob Christmas! premiered.
23 new episodes premiered this year.
- January 17 - Sleepy Time and Suds premiered.
- February 14 - Valentine's Day and The Paper premiered.
- March 15 -Arrgh! and Rock Bottom premiered.
- March 22 - Texas and Walking Small premiered. Plankton became a main character of the show.
- April 1 - Fools in April and Neptune's Spatula premiered.
- April 8 - Mermaid Man and Barnacle Boy II and Hooky premiered, ending Season 1. Mermaid Man and Barnacle Boy were no longer minor characters.
- October 26 - Something Smells and Bossy Boots premiered, starting Season 2.
- November 2 - Your Shoe's Untied and Squid's Day Off premiered.
- November 15 - Big Pink Loser and Bubble Buddy premiered.
- November 27 - Mermaid Man and Barnacle Boy III and Squirrel Jokes premiered.
- December 6 - Christmas Who? premiered.
- December 28 - Dying for Pie and Imitation Krabs premiered.