Mandalay Bay opened on March 2, 1999, on the southern Strip grounds formerly occupied by the Hacienda. Its gold-glass hotel, tropical recreation areas and casino belonged to a new resort. Hacienda’s demolition and the move of its horse-and-rider sign downtown were separate events in the site’s earlier history.
Hotels and the 2003 expansion
The resort combined different hotel experiences from its early years. The company’s 2004 filing describes a Four Seasons hotel within the property and the addition of THEhotel, a separate all-suite tower that opened in December 2003. The same year brought a new convention complex in January and the Mandalay Place retail connection to Luxor in October. These additions expanded the original 1999 resort.
A growing convention destination
Meetings became a particularly important part of that development. In January 2016, MGM announced completion of a further convention-center expansion with the opening of the Oceanside Ballroom. The announcement distinguished the completed meeting facilities from room-redesign work still under way. The campus grew through successive projects rather than one opening that delivered every later feature.
THEhotel, Delano and W Las Vegas
The all-suite tower also changed names. THEhotel became Delano Las Vegas in September 2014. On December 18, 2024, MGM and Marriott marked its debut as W Las Vegas. Those are changes within the connected Mandalay Bay campus; they do not move the main resort’s 1999 opening or turn its casino into three successive properties. The illustration adapted from a 2025 photograph shows W in the foreground and the main Mandalay Bay hotel behind it.
The 1 October attack
The resort’s later history includes the mass shooting of October 1, 2017. A gunman fired from a Mandalay Bay hotel room into the crowd at the Route 91 Harvest music festival. The attack killed dozens of people and injured hundreds. The police department’s public records preserve the investigation; that tragedy is part of the place’s history alongside its development as a hotel, casino and convention destination.
The resort and its predecessor
Mandalay Bay remains listed as a licensed Strip casino in Nevada’s June 30, 2026 gaming report. The hotel brands and convention spaces help explain the connected complex visitors see today. They also make the distinction between the demolished Hacienda, the main Mandalay Bay building and the later all-suite tower essential when reading old photographs or following a map.
