Yemen is 71% larger than Oman.
Area: 309,500 km2 World Factbook
Population: 3,219,775 (July 2014) World Factbook
Oman, officially called the Sultanate of Oman, is an Arab state in southwest Asia on the southeast coast of the Arabian Peninsula. It has a strategically important position at the mouth of the Persian Gulf. Wikipedia
Area: 527,968 km2 World Factbook
Population: 26,052,966 (July 2014) World Factbook
Yemen, officially known as the Republic of Yemen, is an Arab country in Western Asia, occupying the southwestern to southern end of the Arabian Peninsula. Yemen is the second largest country in the peninsula, occupying 527,970 km². The coastline stretches for about 2,000 km. Wikipedia