When should I tell my employer that I don't plan on staying after my internship?

Question

I am a PhD student in the UK due to start a three-month internship in a startup within the next two weeks. When I was made an offer (a couple of months ago), the company pushed very hard to offer me a permanent position. I insisted on the three-months internship because this is my first job post-PhD.

After signing the contract (with the mutual understanding that if all goes well I will stay for a permanent position after the internship), I got an opportunity to spend three months in a research group. This is a professional opportunity that I absolutely do not want to pass on, so I accepted, and am due to start right after the three months internship.

When should I tell the startup bosses that I am definitely leaving for three months after the internship? Depending on how it goes I wouldn't mind then coming back to the startup and taking on a permanent role, so I would like to roll this out in the best way possible.

UPDATE I ended up telling them during my second week, mentioning it as an opportunity I hadn't yet accepted but did not want to refuse, and asking them how open they would be to a delayed start to my permanent contract. They served me my notice immediately, and seem intent in giving me no meaningful work for the next month. In hindsight, I should have told them much later, as that would have given me two more paid months.

Answer 1

Talk with your manager now, there's little to gain by waiting, but there is a lot to lose by not giving as much notice as you can.

Some things you should consider:

1. Give as much notice as possible. Give your manager a chance to keep critical work that you're working on going after you leave. If the organization knows you're leaving, other colleagues can overlap with you on your work to avoid delays due to unplanned handovers.

2. Share your aspirations with your manager. The company may be willing to be accommodating (e.g., give you 3 months of leave to pursue the research). If coming back after your research experience is something you're open to - start the conversation now to see if that might be possible.

3. In general, honesty and transparency yield the best results. Keeping your intention to leave to yourself is a risk. Your colleagues and manager learning about your departure from someone else increases the risk of "burned bridges."

Answer 2

What is the notice period for your internship?

If there is a mutual understanding that you would convert to full time at the end of your internship, then that notice period length is the smallest amount of time you can give your manager while remaining professional.

When you give your notice, be sure to tell them about the research group that you're leaving for. You don't need to do this (and in fact you don't owe them any explanation of why you're leaving at all), but if your manager is a reasonable person then they'll understand the value of the opportunity to you, and won't begrudge you taking it.

If you've given an appropriate amount of notice, and made it clear that you're not leaving because you don't like the company, then you're unlikely to have burned any bridges and your manager may be open to offering you employment at the end of your research group period.