I am an Indian citizen, travelling to Germany with a 24 hour layover in Oman. I would like to explore Muscat during my layover, but it is unclear if I need a visa. Some places on the Internet say Indians with US visas (which I have), do not require visas, while others do. Oman Air themselves did not know either. The embassy in New Delhi is also unhelpful.
The Omani government visa webpage does not address the basic question of whether an Indian citizen needs a visa (or transit visa) to enter Oman. Other Omani government pages do mention tourist visas and transit visas for tourists on their way to other destinations. All in all, the official answer is unclear.
On the other hand, this secondary source states that Indian citizens are visa-exempt and may enter Oman freely.
I would contact the Omani government authorities directly and ask. Multiple contact methods are presented on many of the Omani government pages.
According to the Omani Foreign Ministry, you are exempted from visa requirements for touristic entry.
The countries and regions whose nationals are exempt from entry visas to the Sultanate for a period of 14 days, subject to certain requirements, are listed below.
Now, it requires a hotel booking :
The exemption is subject to certain requirements including a prior and confirmed hotel booking, health insurance, and a return ticket.
so it might not be practical in your case (depending on the layover timing, you might not even be able to book a hotel room (I don't know if you can book day hotel stays in Oman))
If you fulfill those requirements, you're likely good to go