The shell obby appears to be in the lighthouse area / near the sea , based on recent gameplay videos about the summer event in Restaurant Tycoon 3, not a clearly documented Restaurant Tycoon 2 location.

What that means

  • In the video walkthrough, the player says to go to the lighthouse area to find Shell Obby.
  • Another walkthrough describes the new summer obby as being near the sea and labels it “shell obby.”

Important note

  • Your question says Restaurant Tycoon 2 , but the results I found point to Restaurant Tycoon 3.
  • I couldn’t verify a confirmed Shell Obby location for Restaurant Tycoon 2 from the available results.

Fast tip

Try heading to the beach/lighthouse side of the map first, since that’s where the shell obby is described in the newest guides.

TL;DR: Shell Obby seems to be by the lighthouse, near the sea , but the evidence I found is for Restaurant Tycoon 3 , not 2.