Hello everyone! This is a friendly reminder that any of these fun places we may visit, we are a guest at. Please treat both businesses and trails with the utmost respect. We here at Hidden San Diego follow the 'Leave no Trace' mantra, meaning whatever you bring with you comes back with you. If you see trash on a trail, please do your part to help remove it. Remember, we are not picking up trash from another person but instead cleaning up for Mother Nature. Happy adventures!


Dog-Friendly: No   Kid-Friendly: No

**No-Trespassing Zone**

Personal Experience: Tunnels are not usually my thing. They go on forever and once you're deep in there, you have no way out besides trekking forward or trailing back the same way you came in. On top of that they are pitch black inside, dirty and definitely not for those with extreme claustrophobia. With that out of the way, who's down for a real adventure?

This was a crazy time. It took many months of my friend persuading me into embarking upon a tunnel of this size. I finally caved in though. We went maybe 1.5-2 miles in and had some light show fun deep inside. All was well at the beginning.

My friend is mapping out the entire underworld of San Diego and asked if he could quickly map out one of the small inlets from the main tunnel we were in. I said sure. Well, 30-40 minutes goes by and he's still not back. I call his name. No answer. I scream his name. No answer. I scream it again and again and still no response. This is when I realized that I was several miles inside a super-creepy tunnel, a small female (thankfully with some protection as I recommend you always bring too) and alone. I decided I was not going to wait any longer for him because who knows how long he may be.

I pretty much ran back, the light bouncing up and down off the ceiling and ground and looking and feeling as if I were in a horror movie. It was a nightmare come true and thankfully nothing bad happened. I made it out okay and unscathed. Will I be tunnel exploring with my friend again? Probably not. 🙂


There are several different sections and multiple inlets that will take you different directions. Be careful not to get lost! We just went straight and still didn't go all the way through. We went maybe 35 minutes in I'd say.It is pitch black inside the tunnels. Not an inch of light. Make sure you have proper lighting. Here is a better example of how dark it is inside, but still, imagine it pitch black:

alvarado tunnel

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3 Reviews

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3 Reviews


  • Jonathan
    Rating Overall Rating Difficulty Finding

    I wish this wasn’t for members only…. 🙁

    July 24, 2016

  • Vista_4_Life
    Rating Overall Rating Difficulty Finding

    Did you find your friend?

    August 4, 2016

  • Anonymous
    Rating Overall Rating Difficulty Finding

    The picture of the cockroach is enough to keep me out.

    October 23, 2018

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