Trade through the Miami Customs District, which includes all South Florida airports and seaports, broke the $100 billion threshold in 2011 and accounted for 3.06 percent of all U.S. trade.

A trade analysis released Friday by WorldCity, a Coral Gables media company, showed that total trade through the Miami district was a record $112.8 billion in 2011. Exports at $69.26 billion and imports at $43.56 billion also broke records. A weak dollar, which makes U.S. exports more competitive, was responsible for some of the export surge.

The Miami district’s share of total U.S. trade was its best showing since 1998.

Despite the record numbers, the WorldCity analysis showed that the Houston Customs District is continuing to erode Miami’s position as the U.S. gateway for trade with Latin America. Houston with its oil-based economy, for example, is now the top hub for U.S. trade with such key markets as Brazil, Colombia, Venezuela, Chile, Costa Rica and Argentina.

And Houston is close to overtaking Miami as the main gateway for trade with Guatemala and Peru.

Much of the trade through the Miami district is export-based, leading to a record trade surplus of $25.7 billion — the highest ever recorded by a U.S. Customs district.

But since relatively few of the exports handled by South Florida’s ports are made in the state, the Miami District’s large trade surplus doesn’t represent more manufacturing jobs as it would if the nation as a whole ran a trade surplus. The jobs generated by Miami’s international trading sector are largely service jobs.

“Miami’s role is that of the shopping cart for Latin America — mostly exports,’’ said Ken Roberts, president and chief executive of WorldCity. “A lot of Houston’s trade is imports.’’

Brazil with two-way trade of $15.15 billion with the Miami district — a 12.4 percent increase — continued as South Florida’s top trading partner. Rounding out the top five were: Colombia ($8.28 billion), Switzerland ($7.78 billion), Venezuela ($6.7 billion) and China ($5.68 billion).

Switzerland and the United Arab Emirates were South Florida’s fastest growing trade partners. They are both large importers of gold, which arrives in South Florida from Mexico and Colombia, and the run-up in gold prices has helped boost trade figures. Exports of computers to the United Arab Emirates also are showing growth.

Trade with Switzerland was up 3,510 percent over the past decade and trade between UAE and the Miami district increased by 1,105 percent over the past 10 years.

Other countries whose trade with the Miami district showed significant increases last year were Vietnam, Paraguay and China, which has a huge trade surplus with the United States. China trade was up 11.5 percent year over year and up 356.4 percent over the past decade.

Because of poor labor conditions for workers and shipping and quality problems, some U.S. companies are having second thoughts about manufacturing in China, said Barry Lawrence, a supply chain expert at Texas A&M University.

“The vast majority of U.S. companies manufacturing in China and shipping to the United States should not be doing it,’’ said Lawrence, who spoke at the WorldCity event.

But, he said, they are reluctant to abandon China — and its potentially lucrative internal market.

If a company shuts down a plant in the United States and workers lose jobs, it has a public relations problem, he said. “If you leave China, you’ve got a lot more than a p.r. problem. You might not be able to come back.’’