The most common route taken by US Navy ships is the "Great Circle Route," which takes the ship across the Pacific Ocean, then through the South China Sea and the Indian Ocean, and finally into the Persian Gulf. This route covers approximately 12,000 miles and can be traveled in about 30-35 days.
Other routes that can be taken include the Panama Canal route, which takes the ship through the Panama Canal to the Caribbean Sea and then across the Atlantic Ocean to the Mediterranean Sea and finally into the Persian Gulf. This route covers approximately 13,500 miles and can be traveled in about 45 days.
The speed of the ship also plays a factor in how long it takes to travel from San Diego to the Persian Gulf. US Navy warships are typically capable of speeds of over 30 knots, but the speed at which they travel will depend on a variety of factors, including weather conditions, fuel consumption, and the need to maintain a certain distance from other ships.
Finally, any stops that are made along the way will also add time to the journey. For example, US Navy ships may stop at ports in Hawaii, Guam, Singapore, or other countries to refuel or take on supplies. These stops can add several days to the overall travel time.