The Dominican priests originally built the Diplomat Hotel as a seminary in 1911. It functioned as a school for many years before the government converted it into a hotel. According to lore, when the Japanese conquered Baguio, many Filipinos, including soldiers, priests, and nuns, were killed and decapitated.

The hotel was managed by Antonio Agapito "Tony" Agpaoa, a Baguio-based entrepreneur and faith healer famous for psychic surgery. Agpaoa suffered a heart attack and was diagnosed with brain hemorrhage in the 1980s. He died in 1987 of the ailments. Since his death, the hotel ceased operations and was abandoned.

On August 29, 2014, Thayer Lodging Group bought the Westin Diplomat Resort and Spa for $535 million. In 2023, the hotel changed hands again when Trinity Real Estate Investments and Credit Suisse Asset Management acquired the hotel by a record-breaking $835 million dollars deal.

The Diplomat Beach Resort, Curio Collection by Hilton is South Florida's iconic beachfront destination located near Miami and Fort Lauderdale, in Hollywood, Florida.