Can you work in Singapore and Japan both with two work visas?

Question

I've tried to search similar questions but none is specific to my need.

• expatriates.stackexchange 1: work in two different countries
• expatriates.stackexchange 2: hold two work visas in two countries

Situations: I'm a Malaysian, currently working in a startup in Singapore for about 4 years but I'm still under employment pass. I just received a lucrative offer in Japan and wondering about the possibility of working two jobs.

Questions: I need help from someone with immigration and tax knowledge for so that I don't get in trouble by the immigration and IRAS of Singapore or Japan. Here are my questions:

• Is it legal for workpass holder in Singapore to also hold workpass visa in another country, working for two completely different companies?
• Is it legal for workpass holder in Japan to also hold workpass visa in another country?
• If it is illegal but I will still do it for about 6 months. How easy is it to get caught?

My Plan

• I have both workpass visa in Singapore and (soon) Japan Both employer in Singapore and Japan don't know each other. Also they are not connected at all.
• My work nature is mostly work from home. I'm a data scientists.
• I'll stay in Singapore for 183 days and Japan for 182 days. Alternating between 2-3 months for 6 months. (Will I get caught?)
• I'm capable handling two jobs in a day and can work 2x productivity, assume both employers in SG and Japan won't have clash meetings too.
• I'll pay tax to both Japan and Singapore for each respective job.
• After 6 months. I probably choose Japan for better living.

What I understand:

• Working in Singapore, you can only have 1 workpass in Singapore according to the official. But doesn't say if you have two jobs in two countries?

• Both company has different market, one is finance. One is e-commerce. As long as I didn't work in finance or e-commerce. I assume no consequences?

• In Singapore, a workpass visa require 183 days in one tax year at least. Not sure about Japan though.

Answer 1

From an immigration point of view, what you're proposing is fine. You're legally employed in Japan, you're legally employed in Singapore, neither country cares what you do outside its borders. In Singapore you even get tax breaks if you spend a lot of time traveling outside the country!

From a taxation point of view, this sounds very complicated to do legally and you'd definitely want to get professional tax advice.

Last but not least, virtually all employment agreements prohibit working other jobs without explicit permission, so your employers would almost certainly object to this scheme. Working two jobs in one city is hard, doing so from two different countries with different time zones, holidays etc strikes me as very difficult. At one point in my consulting career, I was simultaneously engaged on two large projects in different countries, and this was hard enough even with the full approval and encouragement of my employer.