Miyazaki Beach

From July to August is offical swim season in Miyazaki.

Beaches in Miyazaki City (South Miyazaki)

Aoshima Beach

Nagisa no Koban Facebook Page with updates if the beach is open
https://aoshimabeachpark.com/

This beach is great for surfing. During swimming season adults cannot go in further than standing in order to protect the children.

Shirahama Beach

Google Maps
10 minutes walk down from Aoshima beach you can find Shirahama Beach with less people and less rules. There are some shops. Shower available.

Parking Lot is 500 yen.

Beaches in South Miyazaki

Futo Beach: 20minutes south from Aoshima Beach.
Miyazaki Area Guide | Futo Beach - Miyazaki’s Most Beautiful Swimming Beaches | Mountain Swell

Beaches in Nobeoka (North Miyazaki)

Nobeoka arguably has the best beaches for swimming in Miyazaki Prefecture.

In Nobeoka we recommend Sumie Beach for a nice splash in the ocean.
There is more than enough parking and some shops, but it is very relaxed. It takes about 1.5 hours by highway from Miyazaki City, but it is worth it.

Shimo Aso beach is another good choice.

Source: Explore Nobeoka