Hi there! I have not personally been in your position, so take everything with a grain of salt, but here's my thoughts on the issue:
I am not aware of there being a general policy of either allowing or disallowing this across law firms. Thus, the answer to your questions will depend on a firm-by-firm basis. I think you should take the following into consideration when deciding whether to apply to the same firm in different offices.
- Firstly, have a look at the firm’s application policies and processes (including the FAQ page), which you should find on their website. You might not find anything addressing this particular issue, but you might still find clues as to the firm’s potential attitude in the language they use. If they emphasize particularly heavily that you can only apply to one position per cycle, and if they do not qualify that in relation to the office, the firm might be disinclined to consider application for two different offices.
- Secondly, you can have a look around the application portal and application processes at the two offices. If they are very similar and look to be highly-centralised, the same recruitment team might be handling all the applications and thus making two applications might be a higher risk. However, if it looks like the recruitment process is being run independently from each office, the firm’s recruitment team may not even know you are applying in two places. Thus, the firm's policy is likely that the two offices can each consider your application.
- Thirdly, the slightly more time-consuming, but most effective way of handling the issue would be to reach out to the firms’ graduate recruitment teams directly. You can either try emailing, or sending direct LinkedIn messages, or both – it is very unlikely that any recruiter would mind your query. If anything, it demonstrates interest and a proactive attitude.
Finally, I would suggest that if you do decide to apply to two offices, you should flag that in your application portal. Some firms may not even have a determinate policy of whether this is allowed or not - what will matter most then is if you can demonstrate transparency, that you did not try to conceal multiple applications.