The bedroom is located on the second floor of SpongeBob's house and has red bamboo wallpaper on the right side and blue metal wallpaper on the left. The left side also contains a porthole window from which the inside of Squidward's house can be seen.
In the middle there is a bed that contains three white mattresses, bamboo sticks used to hold them together, a white pillow, and a green buoy with dark green rings. Above his bed is a diving board connected to a ladder, which appears to be used to jump from one room to another to put on his clothes, as seen in "Help Wanted."
Objects in his room include a foghorn that serves as an alarm clock, which sits atop a barrel, a food bowl from which his pet snail Gary eats, piles of newspaper near the bowl (which presumably serve as a place for Gary to use the bathroom), a toy treasure chest, a scallop that hangs in a birdcage, and a giant calendar.
There is also a closet in the room, in which SpongeBob stores his pants.
The season 5 episode "Night Light" shows that there is another bathroom attached to the bedroom.
SpongeBob's bedroom is a recurring location in the series and is often seen at the beginning of an episode when SpongeBob wakes up in the morning and his foghorn alarm goes off. SpongeBob, Gary, and Shelley all sleep in this room. SpongeBob has also had a few roomates throughout the series.