Jodogahama Beach in Miyako city (Iwate pref.)

Story short, during my trip around Tohoku area I want to visit Miyako city and Jodogahama Beach. But as my budget is rather low and hotels/hostels in Miyako city arent't the cheapest ones, I'd like to spend the night at the said beach. Is it even possible to do that? Are there any guards or something like that? Is the beach lighen up during the night? I must admit that I'm a girl and I'd like to live through that night :)

In general (except in Okinawa, perhaps) Japanese don't go to the beach unless in summer. So you probably won't see any guards or patrol. But it can get very windy and cold. I went to Jodogahama beach in spring once, and I don't remember seeing anybody on the beach. Personally, I don't recommend it for a solo girl.

Just go back to Morioka at the end of the day?

I understand your dillema as I was facing similar problem when planning for Jodogahama. The best option is either to stay at Park Hotel or return to Morioka. Maybe I'm not an adventurous person, but I've been to several beaches in Japan and would not recommend to stay there without permission.