The tunnel is open daily...one certain busy holidays...the tunnel may be open just one way...but there will be detour directions to direct you over the Marin headlands west of the Golden Gate Bridge... Hope that helps...
To answer Mr. Bijala’s question, since none of you did properly, the tunnel on the walking path to the lighthouse is open ONLY on Sundays & Mondays, 12:30-3:30. NOT 4:pm. NOT 5:pm. The one-way tunnel on Bunker Rd from the 101 is open all the time, I believe. It’s a main road for the public, local residents and park employees.
I believe it closes at 5pm. Get there before 4pm so you can take your time and take in all the scenery.
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