Can I work remotely for a non-Singapore employer while visiting Singapore?

See answer to #10 in here: legal500.com/guides/chapter/singapore-corporate-immigration

It clearly says:

Remote work can be carried out provided that the work activities do
not benefit a local Singapore entity. In such scenarios a work pass
sponsored by a Singapore entity is not required.

In the EU it is the location of the company for which you work that decides where you must pay taxes. If I live in Germany and work as a fixed employee for a Danish company, the taxes must be paid in Denmark. But only as a fixed employee. As a freelancer I would have to pay taxes in Germany, because then I would have my own company in Germany.
This is due to the EU laws, to which all other laws must conform.
The sentence "The above activities should not involve a contract of service or a contract for service with an employer in Singapore." could hint that it is something similar in Singapore.
It should be checked of course.

EDIT:

This used to be the rule of thumb, before covid. Danish tax has clarified the rules and now it is affected by work-from-home days:
"If, as a result of corona/COVID-19, you are working more from home (in your country of residence) than you used to, it could mean that you are liable to pay tax in both your country of residence and in the country where you work. As result, you should check your tax assessment notice and consider whether you need to make any changes for 2021."
(https://skat.dk/data.aspx?oid=17032&lang=us)

So, can I work remotely for my US employer while visiting Singapore?

That can broken down into 2 different questions:

Is it legal?

Unclear. Most countries laws have not caught up with the realities of remote working and don’t specifically cover this case.

What would happen if you do it?

Absolutely nothing. No one cares. Firstly, the likelihood of some officials finding out is extremely small. And even if they do, they wouldn’t know how to handle it and what to do with you.

The laws are mostly written under the assumption that the work that you are doing is somehow causally related to your presence in the country. That’s simply not the case for remote work and so it’s all up to interpretation.

The strictest interpretation would be "You are not allowed to check work e-mail while in country". That’s off course preposterous and no sane country would ever enact or enforce such a law as it would kill its own tourism industry.

So as long as what you are doing can be considered "reasonable" you are fine. Until we have a legal definition (through the courts or through an actual law) what "reasonable" means, I’d go with "what everybody else is doing".

The thing is, that millions of people do this every day and I haven’t heard of a single case where that was a problem. The absence of court cases is also a sign that most governments are fine with the status quo and don’t WANT to deal with it.

The answer is… it depends on your work!

Visitors entering Singapore for business or pleasure are issued a Short-Term Visit Pass (STVP) that allows them to do the following business activities:

Attend company meetings, corporate retreats or meetings with business partners.
Attend study tours or visits, training courses, workshops, seminars and conferences as a participant.
Attend exhibitions as a trade visitor.

(courtesy Ministry of Manpower)

The same page also has a longer list (too long to quote here) of other activities that can also be performed on an STVP if you notify MOM, including things like organizing conferences, commissioning equipment and participating in exhibitions.

So, can you work from Singapore for your US employer on an STVP? If you’re a typical executive whose work consists of attending meetings, yes, you can! But if you’re doing something like writing code for customers that aren’t in Singapore, you’re legally in a grey area. Realistically speaking, though, Singapore is very business friendly and as long as you’re not getting paid by anyone in Singapore or trying to visa run your way around the 30-day visa free period, you’ll be fine.

Note: I am answering from a legal perspective, without any ‘it’s only a short time, you’ll get away with it’ suggestions.

The answer is no. The Singaporean government website states:

All foreigners who intend to work in Singapore must have a valid pass (commonly known as a work visa) before they start work.

There are very few countries that allow to just work remotely, even if the company isn’t in that country, and the ones that do wouldn’t allow it on a visa suited for tourists, or visa-free arrival. Technically even answering a work email isn’t allowed but a country wouldn’t be smart to enforce and punish that. But go beyond that and the law is pretty obvious. There are many rules about labour and once you’re not a tourist mainly depositing money, they want you to follow those rules and pay taxes. It doesn’t matter where your employer is located. A local couldn’t just work for a foreign company and avoid paying taxes in their life either.

The term for this is digital nomad, there are SOME countries that have something resembling a digital nomad visa, but Singapore is not one of them. It does have a Work Holiday visa but it’s heavily regulated and quite limited in who can apply. In any case, on a tourist visa (officially eVisa, but only needed for a selected number of countries) or visa-free arrival, work is never allowed.

Countries simply mostly haven’t quite adopted to work nowadays being quite possible to do with just a computer and internet, and reasonable taxation on those people is a difficult thing to both determine and enforce. So usually the old work laws just apply, and you’re not able to legally work any more than a manual labourer trying to get a job in a better-paying country.

Of course many people work remotely anyway and get away with it.