But the ocean route for these immigrants is not always a direct one. On a cold and wet day, a group called the Desert Angels traveled to the northern end of the Coronado Islands in Mexican waters.
The group says immigrant smugglers use the place in an attempt to throw off U.S. tracking techniques. Some immigrants are dropped at the location temporarily. But when the weather is bad or the Coast Guard is searching, the immigrants are left behind, sometimes for days without food or water.
Rafael Hernandez and the Desert Angels have no political agenda, except to ensure that human beings don't die because they're without food or water.
As Hernandez and his partner Ricardo Villegas began to unload the food and water, it didn't take long before their last drop served its purpose.
There is an element of danger because they've crossed paths with drug traffickers in the past who also use the islands.
With the drop completed, the Desert Angels searched for abandoned immigrants who may be hiding and in need of medical care.
No immigrants were found, but the Angels did discover the island was used recently.
The Desert Angels also help immigrants stranded in the desert. They say the fee for those boat rides into San Diego is $2,500 to $5,000.
That form of smuggling has nearly doubled in one year.