Are these good A level choices?

There are no required A levels for law, and any of those which you mention would be fine. Please think carefully before taking four A levels. You only need to take three. Taking a fourth does not enhance your prospects of success, and may harm them.
Strong maths students aiming to study maths, physics, or computer science at university might add Further Maths as a fourth A level. For others, there is little or no point in a fourth A level.

I’m about to pick my a level options for sixth form and I was wondering whether I could have some advice on what I should pick.
I plan to do law (and hopefully specialise into environmental law in the future) and was thinking of doing biology, physics (I really enjoy physics so I’d like to keep this), maths and politics.
Is this a good combination? Is politics classed as an essay based subject? Would it be better if I swapped maths for something like English lit or history?

Biology could be smart if you’re planning to venture into environmental law and enjoy it, same with Physics really although perhaps less relevant but an excellent choice if you’re passionate about it!
Yes, Politics is an essay based subject and from what I know is a great choice for getting some knowledge of the legal system broadly speaking so could help you toward your goal and be a good subject to discuss on your personal statement in the future.
For Law they want high grades and taking 4 a levels could jeopardise this. The way I think about it is that if you take 3 subjects you’ll have perhaps 15 hours work to do outside of classes and say 5 hours of study periods per week to do it in- so 10 hours of work to do outside of school. For 4 subjects it’s closer to 20 hours outside of class and a pretty much full timetable so that’s twice the workload outside of lessons. However it is your choice!
My advice would be to do 3 (Biology, Physics and Politics) and you could also consider an EPQ if you wanted. I wouldn’t take 4 in your situation because you may also have to do the LNAT depending on where you apply and maintain high grades.
The exception to this would be if you want a career in law but you plan to do a STEM undergrad then a law conversion year to become a lawyer, in that case consider what kind of STEM degree you would look into and see if Maths is required or not (should be fine for biosciences but likely not physics).
Hope this helps and happy to try answer any more questions if you have them. Have a great day

I’ll keep your advice in mind when I pick my options! I hadn’t taken the LNAT into account for things I’d have to study for so thank you for reminding me
Do you know around about how much time I might have to put into the LNAT? If you’re not sure that’s totally okay
Thanks again

Im unsure but from what I know from other you’ll have to do and mark some practice papers. The papers are 2.25 hours long (assuming you dont have extra time or anything) and with any and all tests I would recommend doing them in timed conditions, marking them thoroughly then attempting the questions you did not have time for. So in total per paper you could be looking at 3-4 hours if you do a proper job at learning from it!
You are advised to read a lot (the LNAT website actually recommends reading a newspaper daily) and ask yourself questions about the newspaper:

Id agree this is a good exercise as for politics im aware you’ll have to keep up with current affairs so it’s advisable. Depending on how fast you read this could take a chunk of your day up if you do it consistently and thoroughly but it’s up to you.
Also its probably advisable to practice essay questions by planning them, in a past paper you’ll answer one but as part of the consolidation i mentioned with answering other questions in the past paper you could answer the others in bullet point format or write them out fully depending on which you find most representative of your ability with the time constraints of your workload and then mark them too.
I hope this is somewhat accurate and helpful, I dont know a lot about the LNAT and mostly got this from their website plus my own knowledge of how to effectively utilise past papers- its the method i used for my GCSEs and hopefully it has served me well, although I wont know til Thursday (eek!).
Best of luck with your decision and future endeavours