"I don't think it's really fair how he has the choice to separate us", said Gonzalez, a dual citizen who lives in Tijuana and crosses the border daily to work at a San Diego ramen restaurant.
Demonstrators draped themselves in USA flags and waved placards emblazoned with slogans such as "Humpty Trumpty will fall off his wall", "Resist unstable idiot", and "No hate in the Golden State".
Trump appeared engaged as he was briefed on eight towering prototypes, including one with blue steel on top.
The environmental group and state government were part of a recent lawsuit against the federal government's plans to build the wall in California.
Mexico could be off the hook for the multi-billion dollar bill for President Trump's border wall - as the commander-in-chief tweeted Tuesday about a report that contends the barrier will pay for itself.
Protests are also planned across the border in Tijuana, Mexico, as Trump examines the 30-foot-tall (9-meter-tall) prototypes created to fulfill his signature campaign promise.
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Homan said Pelosi's comments about federal agents terrorizing immigrant communities were "beyond the pale" and challenged Feinstein to change laws if she disagreed with how they are enforced.
The visit isn't Trump's first visit to the border. The mayor's office said Faulconer has been clear in his opposition to walls along the border but he did not want to blacklist companies involved in the construction of the prototypes.
"I'll take you to East L.A. and Boyle Heights, " he said. "No wall!" near the San Ysidro crossing, where tens of thousands of people enter the USA daily from Tijuana, Mexico, many on their way to work or school in San Diego.
Trump is scheduled to fly into Marine Corps Air Station Miramar at 11:30 a.m. Tuesday, then head to Otay Mesa to view the 30-foot-tall border wall prototypes that have been erected there.
Throughout the 2016 election, Trump campaigned on building a border wall and promised that he would make Mexico pay for it.
Trump is talking about sanctuary city policies during his visit to San Diego and inspecting border wall prototypes before heading to L.A. An administration official, who refused to be identified, said the savings - for which no substantiation was provided - would come from keeping out immigrants trying to enter illegally and in that way reduce costs for social services and law enforcement.
Brown sent a letter to Trump Monday in advance of the president's visit, hailing California as "the sixth-largest economy in the world" and saying the state is "thriving", having added "almost 3 million jobs since the recovery began".
The president will also attend a Republican party fundraiser in California.