Cambodia is currently one of the most open and visitor-friendly countries in Southeast Asia following COVID-19 travel restrictions.

Still, the country has not reinstated its pre-COVID-19 visa-on-arrival system, so it is necessary to arrange an online e-visa before you travel.

Do I need a visa to visit Cambodia?

The simple answer is yes: most nationalities need a visa to enter the Kingdom of Cambodia, including citizens of Australia, the European Union, the UK and the US. The main exceptions are citizens from the Association of Southeast Asian (ASEAN) neighbors who are granted visa-free access; these countries include Singapore, Thailand, Malaysia and Vietnam. Some other Asian nationalities, including Japan and South Korea, may also enter Cambodia without a visa in most circumstances. Citizens of Afghanistan, Algeria, Bangladesh, Iran, Iraq, Nigeria, Pakistan, Saudi Arabia, Sri Lanka and Sudan need to make advance arrangements for a Cambodian visa.

A 1-month tourist visa costs US$30; easily extendable business visas cost US$35. Online tourist e-visas cost US$36, which includes a US$6 processing charge.

 

read more https://www.lonelyplanet.com/articles/visa-requirements-for-cambodia

 

Visa on arrival has already been reinstated.

I've seen a couple of reports that VOA passengers are being refused boarding by Singapore Airlines. 

Both reports were from Frankfurt.

 

Does anyone have any information on the current situation flying LHR to Siem Reap via Singapore?

21 minutes ago, Green Machine said:

I've seen a couple of reports that VOA passengers are being refused boarding by Singapore Airlines. 

Both reports were from Frankfurt.

 

Does anyone have any information on the current situation flying LHR to Siem Reap via Singapore?

How recent were these reports?

 

The VOA was only just reinstated.  Literally just 1 week ago.

Last couple of days on the reddit Cambodia page.