Navy
Yokosuka harbor security crews practice responding to intruding vessels
Stars and Stripes
June 12, 2026
Sailors practice securing the port from an intruding vessel during an exercise near Yokosuka Naval Base, Japan, on June 9, 2026. (Akifumi Ishikawa/Stars and Stripes)
YOKOSUKA NAVAL BASE, Japan — The Navy recently rehearsed harbor defense at the home of the U.S. 7th Fleet, training security forces to respond to unauthorized vessels approaching the installation.
The exercise involved two harbor security boats operating in a designated area of Yokosuka Port and firing blank rounds from mounted machine guns.
The drills were scheduled for Monday to Thursday, although no training took place on the first day. It marked only the second time the exercise has taken place since being introduced in 2024.
On Tuesday, one harbor security boat served as the intruder while another attempted to intercept it.
Yokosuka city officials stationed at Verny Park, which has a view of the harbor, counted roughly 1,900 blank rounds fired that day, according to the Kanaloco online news website.
The harbor remained open to civilian and Japan Maritime Self-Defense Force vessels, but training was paused each time a vessel came near.
Tuesday afternoon, a sailboat operated by the Yokosuka Peace Flotilla anti-war group entered the training area, interrupting the exercise for about 20 minutes. The vessel, whose sail featured a peace sign and a rainbow flag, was intercepted by a Japan coast guard ship.
The Navy first introduced the harbor security drill in 2024 as part of efforts to strengthen force-protection capabilities in and around Yokosuka Port, home of the U.S. Navy’s largest overseas installation.
The Yokosuka Peace Flotilla, an antiwar group, interrupts harbor defense training near Yokosuka Naval Base, Japan, on June 9, 2026. (Akifumi Ishikawa/Stars and Stripes)
Sailors practice securing the port from an intruding vessel during an exercise near Yokosuka Naval Base, Japan, on June 9, 2026. (Akifumi Ishikawa/Stars and Stripes)