Mr Howard died after being admitted to hospital in the city of Colombo on Sunday.
The squad of 22 men is reported to have arrived in Sri Lanka on May 10 and played a friendly match at a ground in Colombo on Saturday.
His teammate Tom Baty, 26, who is thought to be seriously ill, remains in hospital.
The pair were touring Sri Lanka with the Durham-based Clems Pirates RFC.
Thomas Baty and Thomas Howard of Durham, England, had been each admitted to hospital in Colombo on Sunday Could 13, complaining of respiratory difficulties.
The club previously said that in both cases the breathing problems were non-rugby related.
Howard's death was confirmed in a club statement issued on Monday.
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According to the police, the players have returned to their hotel in early morning around 4 am and two of the players had develop breathing difficulties.
"We ask the media to respect the privacy of the families at this very hard time".
After the banquet, British Rugby players had come to the hotel where they were staying and afterwards had gone to a night club in Kollupitiya, the police said.
After the match, the team went out for a meal before they visited a nightclub in the Kollupitiya area of the city.
In a statement released on Monday following the announcement of Mr Howard's death, Durham City RFC president Richard Wilkinson said: "Both players and Clems Pirates hold a special place in our rugby family, and our continued support is unconditional".
"We are assisting the family of a British man who has been hospitalised in Sri Lanka, and are in contact with the Sri Lankan medical services", it added.