Driving to Hachinohe City

Exit the base from the POL gate and proceed straight about 3 KM until you reach the Momoishi Toll road. It is the first overpass you will come to.
Turn left at the traffic light just prior to the overpass and you are on the entrance ramp to the toll road
You will pass through the Shimoda Toll Gate (¥150) and continue on to the Hachinohe Kita exit. (Second exit past the toll booth)
Exit at Hachinohe Kita (¥200) and follow the exit ramp to the traffic light.
The cross street is Route 45.

You are now on the outskirts of Hachinohe City. Continue with the below instructions to get to your destination

Tanesashi Grassy Beach
and Shirahama Sandy Beach

Turn right on Route 45 and follow it for about 7km until you will come to a T intersection with a traffic light.
Turn right. You are still on Route 45.
The road splits for a while. The right lane goes under the cross street. The left and center lanes go up a small hill and thru the cross street intersetion.
It does not matter which you take. They join up again after the cross street.
Continue on Rt 45 for a couple of kilometers and you will see signs for Tanesashi Seashore. Turn left onto Rt 29 and follow the signs.
You will go along some small roads in the older part of town near the seaport.
There are two signs to turn right for the beach and you can take them (I didn't go that way). Or you can continue on for a while and you will see a small sign for a left turn to the beach. This takes you along the coast and some nice scenery.
At the bottom of the hill, turn right.
Follow this road past Seagull Island and the Marine Museum
The road soon shows sandy beach on the left. Follow this winding road until you see two parking lots. A small one on the left and a larger one on the right. You have arrived.
Park in the lot on the left. The lot on the right belongs to the resatuarant on the right.