Twenty-one patrons of Neptune Beach Club in Hampton Bays face drug charges filed by Southampton Town Police over Memorial Day weekend, according to authorities.

Twenty of the suspects were observed ingesting drugs or found to be in possession of drugs in the parking lot of the Dune Road beach club or the adjacent Tiana Beach parking lot over the holiday weekend, police said Tuesday morning. The drugs included cocaine, ketamine, ecstasy, marijuana and gamma-hydroxybutyrate, a depressant that is commonly referred to as GHB.

One additional suspect, Victoria Fogal, 22, of New Rochelle, was charged with selling ecstasy inside the establishment. She was charged with fifth-degree criminal sale of a controlled substance and fifth-degree criminal possession of a controlled substance, both felonies, according to police.

In addition, a 22-year-old Coram man was observed defecating on the dunes of Tiana Beach and cited for public urination, a violation, police said.

Charges for the remaining 20 suspects range from third-degree criminal possession of a controlled substance, a felony, to unlawful possession of marijuana, a violation.

The bulk of the arrests were made on Monday, but arrests were also made throughout Saturday and Sunday, according to Sergeant James Kiernan, who heads the Southampton Town Police Street Crimes Unit. A team of undercover officers spent the weekend trying to buy drugs at the club, Sgt. Kiernan said. While Ms. Fogal was the only suspect to actually sell a controlled substance to an undercover officer, authorities observed the rest of the suspects using drugs outside the club, Sgt. Kiernan said.

Sgt. Kiernan declined to say exactly how many undercover officers were part of the investigation, but said it was fewer than 10.

One suspect, Valerie C. O’Connell, 22, of Staten Island, was arrested by uniformed officers rather than undercover officers, Sgt. Kiernan said. On one evening over the holiday weekend, police observed Ms. O’Connell leave the oceanfront club, climb over the dunes and stumble into the ocean, Sgt. Kiernan said.

After officers pulled her out, they found her to be in possession of ecstasy and charged her with seventh-degree criminal possession of a controlled substance, a misdemeanor, police said.

Those suspects who were charged with felonies were arraigned in Southampton Town Justice Court on Tuesday, Sgt. Kiernan said. He said the rest will likely be arraigned on June 23. Most of the 20 suspects made bail following their arrests, he said.

The following individuals face felony drug charges after the weekend bust: Howard O. Patino, 23, of Corona; and Jefferson Barragan-Restrepo, 25, of Elmhurst.

The following individuals are facing misdemeanor drug charges: Michael E. Rodriguez, 38, of Melville; Matthew P. Bruce, 34, of Huntington Station; Hassena Haider, 31, of Lindenhurst; Bilal J. Parvez, 27, of Jacksonville, Florida; Francisco F. Alcivar, 31, of Woodhaven; Grady B. Pinillos, 21, of East Hampton; Edward Yagudaev, 46, of Brooklyn; Yekaterina Fedotkina, 30, of Brooklyn; Dean Henrys, 27, of Corona; Gregory C. Depetro, 19, of Staten Island; Mark H. Smith, 25, of Ronkonkoma; Brianne M. Flood, 22, of Manhattan; Johnathan Lodato, 25, of East Quogue; and Kaliel DeSilva, 25, of Astoria. Another man from Astoria was charged with drug possession but the charges were reduced under the terms of a plea arrangement in October.

A 26-year-old Levittown woman and a 24-year-old Connecticut woman were cited for marijuana violations.