Seventy percent of the Earth’s surface is covered by ocean.

Submarine Commander Wayne (Scott Brady) goes to an underwater scientific research facility called “Sea Lab” on the ocean floor. He is there to investigate a USO. (Underwater Submersible Object)

The object flies over the installation and lands near the lab. Wayne and Hugh Maddox (Mike Road) go over to the ship along with Sandra Welles (Wende Wagner) to check it out. They enter the ship and find a small cylinder. The dummies take it back to the Sea Lab. It grows. It hatches. It's an alien. It attacks. It somehow breaks out of the facility cutting the lines to the surface. The creature then swims to the surface. It attacks the topside communications facility and kills the people who man it. Then it returns to the ocean. The people in the underwater lab are now trapped. And running out of air.

They rig up a trap and capture the creature. There are the usual conflicts. The Commander wants to kill the creature. One of the scientists wants to communicate with it. The monster wants to kill everyone. The doctor gives it less sedative than he should. Back at the spaceship there are a bunch more cylinders that want to hatch. The lab people are not done with tricky situations.

There are some cool people in this. Sheree North, Gary Merrill, James Hong, Scott Brady. Also some cool toys. A two man minisub and a little hand held mini scooter.

The monster is a little silly looking. And overweight. Of course it’s a guy in a rubber suit. I’m OK with that. There’s only so much you can do with a walking fish. And it does walk when it has to. Actually it’s kind of a waddle. I suppose it’s a little difficult to walk with a fin between your legs.

The space ship and the under sea lab are of course miniatures. That’s pretty easy to tell. A little too easy but if you squint they both look a lot better. It’s kind of a low budget movie that wants to look like a big budget movie. It’s fast paced and there is some excitement. There are also a lot of underwater shots that look pretty decent. Of course I have no idea why they called it “Destination Inner Space”. Anyway, it was OK for a low budget Science Fiction underwater movie. I enjoyed it for the underwater scenes alone.