What is the minimum age to join the army? Currently 15 soon 16

Hello Riley,

You must be at least 16 years old to join the Army as a Regular soldier, you can start your application when you're 15 years and 7 months, but you won't be able to go to the assessment centre until you're at least 15 years and 9 month old.
If you're under 18, you'll also need parental consent to join.

You can find more information here: https://jobs.army.mod.uk/how-to-join/can-i-apply/age/

Will I need both of my parents permission or just one?

Great follow-up question!
Looking at policy, it appears you’ll need the consent of “all appropriate persons”, so to me that sounds like you’ll need both.
It’s definitely worth contacting your local Army Career Centre (ACC) to confirm this. They specialise in recruiting and will be able to give you the latest advice on the recruitment process (the “Ask a Soldier” page is aimed more towards asking soldiers questions related to life in the Army).
You can find your local ACC using this page: https://jobs.army.mod.uk/army-careers-centre-finder/

Thank you for replying so quickly! This definitely helped thank you so much

You're very welcome, best of luck with your journey!

How old do I have to be to join the grenider quard

You only need permission from one parent or guardian. In regards to the grenadier guards you can still apply at 15 years and 5 months it might be 7 but check online when putting in application as parents signature is not required until the interview stage. With this you can attend the AFC Harrogate from 16 you will be on the long course of 40 weeks before moving onto your trade.