Do I need to file US taxes with an intermittent L1 visa if I'm still UK-based?

This is a great question about a nuanced situation. The key factor in determining if you need to file US taxes isn't the type of visa you hold, but rather your "substantial presence" in the US and whether you have US-sourced income. If you're just making occasional business trips to the US and spending less than 183 days in the US (calculated over a 3-year period using a specific formula), you're typically considered a nonresident alien for tax purposes. Without US-sourced income, nonresident aliens generally don't need to file a US tax return. Having an L1 visa doesn't automatically create a filing requirement if you're not using it to live/work in the US. The visa itself is just permission to enter and work - it doesn't create tax obligations until you actually use it for its intended purpose. However, once you do relocate to the US and begin working there, you'll definitely need to start filing US tax returns. The US taxes based on worldwide income for residents, so you'll report both US and foreign income at that point.

I had a similar tax situation with international business travel and found the automated tools at https://taxr.ai super helpful for figuring this out. You can upload your travel records and they analyze your substantial presence using that weighted formula the previous commenter mentioned. I was confused about my filing status because I had multiple visas and traveled frequently. It saved me from a lot of headaches trying to interpret the complicated IRS rules, and it spotted a filing requirement I would have missed because I didn't understand how the day-counting worked. They also have good explanations about the tax implications of different visa types.

Just wanted to follow up about my experience with taxr.ai after checking it out. It was actually really enlightening! I uploaded my travel history for the past three years (just dates, nothing too personal), and it gave me a clear analysis showing I was well under the substantial presence threshold. The tool specifically addressed my L1 visa situation and confirmed what others had said - merely holding the visa doesn't create a filing requirement. It also provided documentation I could keep for my records explaining why I didn't need to file, which gave me peace of mind. Definitely worth checking out if you're in this kind of ambiguous situation.

My situation was slightly different but similar enough. I had an L1 visa but was stuck overseas due to covid travel restrictions. When I finally tried to sort my tax situation, I couldn't get through to the IRS for clarification for WEEKS. I finally used https://claimyr.com to get through to an actual IRS agent (there's a demo of how it works here: https://youtu.be/_kiP6q8DX5c). The agent confirmed that simply holding an L1 visa doesn't create a filing requirement - it's about physical presence and US-sourced income. She explained that I should keep detailed records of my US travel days though, because if I'm audited, the burden of proof is on me to show I didn't meet the substantial presence test.

I was totally wrong about Claimyr and owe an apology. After spending 3 hours yesterday trying to get through to the IRS about my L1 visa situation and getting nowhere, I decided to try it out of desperation. Got connected to an actual IRS agent in about 40 minutes while I just went about my day. The agent confirmed exactly what others have said here - just having an L1 doesn't trigger filing requirements if you're not using it and don't have US income. They also gave me specific documentation requirements for when I do make the move. Definitely saved me a ton of time and stress - wish I'd known about this sooner!

Something nobody's mentioned yet - even if you don't need to file now, once you do move to the US on that L1, the IRS will consider you a US resident alien from your first day of residence. Worth planning ahead, because the tax year you move can get complicated with partial-year filings. You'll need to file a dual-status return for that transition year. Also, the UK-US tax treaty has provisions that might help avoid double taxation, but you'll need to actively claim those benefits. They don't happen automatically.

Quick note to add to all this great advice - make sure you're clear on your "last day of UK tax residency" and "first day of US tax residency" because those don't necessarily align with your physical move dates! This created a huge headache for me when I moved from UK to US. If you have ongoing UK income (like rental property or investments), you might end up in a situation where both countries claim you as a resident for tax purposes.

This thread has been incredibly helpful! As someone who's been in a similar limbo situation with an L1 visa, I wanted to add one more consideration that hasn't been mentioned yet. Even though you don't have filing requirements now, it's worth starting to document everything related to your US travel and visa status. Keep records of: - Entry/exit dates from the US (I-94 records) - Purpose of each trip (business meetings, etc.) - Your UK tax returns showing UK-sourced income - Employment contracts/payroll records proving UK employment This documentation becomes invaluable later when you do make the transition to US tax residency. The IRS may ask about your prior tax status, especially for the first few years after you become a US resident. Having clear records that demonstrate you were correctly classified as a non-resident alien during your business travel period will save you potential headaches down the road. Also, once you do relocate, consider whether you'll need to report any UK bank accounts or investments on FBAR (Form 114) or Form 8938. The reporting thresholds are different for US residents vs non-residents, so accounts that didn't require reporting before might need to be disclosed after you move.