Looking for a full-time job

Hello,

I have been studying in a Japanese university for a year as an exchange student, but I had to go back to my home country to graduate. So now I'm planning to go back to Japan to study at a language school for 6 months and then try to find a full-time job there. The thing is, I know I can work in a part-time job with a work permit, but I don't know when it would be ok to start looking for a full-time job. And in case I get one, what would I do? since I have been told I need to attend the school and complete the course. Also, since my visa would be only valid for 6 months, I don't think I would have enough time to look for a job. So, I would like to know if someone knows (or based on experience), when it's the right time to look for a full-time job (taking into account the school, visa expiration date, etc.)

thanks in advance

You question is very generic, so hard to answer. I assume you are a new graduate and do not have work experience (except student jobs).
In that case normally new graduates are hired in April and are interviewed in and around April the year before.
If you want to work in a Japanese company normally the expectations is to have at least N2, better N1. Depending on the field of work. Will your half year of Japanese language school get you there? You write that your visa is 6 months only. Is there a reason for that? Student visas can be much longer.

And yes, you need to attend school while you are on a student visa. But as soon as you find a full time job, you can change to a work visa and start working. (it probably takes about a month to change visa, assuming that the company provides you with all the documents needed).

Enjoy studying Japanese!

I would suggest you leverage the internet to help you apply for jobs which are looking for non-Japanese staff. Here are a couple of links to get you started

https://www.daijob.com/en/

https://jobs.gaijinpot.com/

If you apply while you're at language school, and you can attend a face-to-face interview, I think you have quite a good chance. You've already demonstrated you can get a visa, so converting from a student visa to a work visa should be trivial.