"It is heartening to know that a man of such international stature remains committed to the development of talent worldwide," Warner, who heads the Concacaf organisation and is a government minister in the Caribbean country, said in a statement released by England's bid team.
"This is a remarkable opportunity for the 200 participants. The fact that, despite his busy schedule, David has taken the time to open this festival, to share his knowledge with the children, is testament to his character."
Beckham will kick off six days of activity with the football festival at the Marvin Lee Stadium on Sunday.
"Trinidad and Tobago have produced some excellent players over the years and the islands are full of young people who love football," said the former Manchester United and Real Madrid star.
"I am really looking forward to seeing the young girls and boys from all backgrounds and their coaches at my academy.
"Encouraging young girls to play football has always been an important part of the thinking behind the academy and it will be great to take this opportunity to also see some of the world's best young women play in the under-17 final."
The David Beckham Academy is an integral part of the England bid team's legacy plans.
The two organisations have committed to delivering a bespoke football and life skills project in each confederation each year until 2017 - if the bid is successful.
Beckham, who was ruled out of the 2010 World Cup because of an Achilles tendon injury picked up while on loan at AC Milan, is able to travel to Trinidad because of a break in his schedule with Major League Soccer team LA Galaxy
Inspectors from football's world governing body Fifa praised England's 2018 World Cup bid at the end of a four-day visit in August.
The hosts for the 2018 and 2022 World Cups will be revealed on 2 December.
Russia is expected to be England's biggest rival for the 2018 prize, with Spain/Portugal, Belgium/Netherlands, the United States and Qatar making up the list of candidates.
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