Taiwan said it intercepted the plane in the east, while China said its aircraft carrier Shandong was involved.
Beijing began the drills on Saturday after Taiwan’s President Tsai Ing-wen met the US House of Representatives speaker in California.
But so far, the exercises have not been as extensive as they were after Nancy Pelosi visited Taipei last August.
Taiwan is considered a sovereign country. China sees it as a renegade province that will eventually come under Beijing’s control – by force if necessary.
On Monday, Taiwan said it saw 70 fighter jets and 11 more boats in the surrounding waters.
A flight path map released by Taiwan’s Ministry of Defense shows four J-15 fighter jets in the east of the island – suggesting this is the first time the Chinese military has simulated an attack from the east rather than the west, which is where the mainland is.
Analysts say the planes likely came from the Chinese carrier Shandong – one of two company-owned carriers – which is currently based in the western Pacific, about 320 km (200 miles) from Taiwan.
China’s military confirmed in a statement Monday that Shandong “participated” in Monday’s drills. It said the fighter jets laden with live ammunition had “conducted several waves of simulated attacks on key targets.”
On Monday, Japan’s defense ministry said that Shandong had also carried out air operations in the previous days.
The Japanese ministry said that fighter jets and helicopters took off and landed on the carrier 120 times between Friday and Sunday.
Also on Monday, the US sent the USS Milius, a guided missile destroyer, through a portion of the South China Sea about 1,300 km (800 miles) south of Taiwan.
China says the ship “entered its waters illegally”, while the US claims the operation complies with international law.
Washington has repeatedly called for restraint from China after President Tsai met with Kevin McCarthy, the third most senior official in the US administration. Meanwhile, Beijing has warned the US and Taiwan of “strong countermeasures” if Tsai meets McCarthy.
China announced the drills after senior foreign leaders – including French President Emmanuel Macron and European Commission President Ursula von der Leyen – left the country.
Macron then urged Europe not to get involved in a confrontation between Washington and Beijing over Taiwan in remarks that drew criticism.
Fleeing China, he told reporters that Europe risked being “stuck in a crisis that is not ours,” and this would make it more difficult to establish “strategic autonomy.”
The Chinese practice started on Saturday after Ms. Tsai returned from a 10-day trip to the United States and Central America.
Last August, the high-profile visit of Former Speaker of the US House of Representatives Ms. Pelosis to Taiwan was followed by four days of unprecedented military drills in which China launched ballistic missiles into the sea around Taiwan. Mrs. Pelosi has been the highest-ranking US official to land in Taiwan since the 1990s.
However, some analysts say such military exercises could have a fading effect over time.
“To maintain the same fear factor, [China] has to increase it more and more all the time because, after a while, their actions will have a normalizing effect,” said Ian Chong, an overseas researcher at Carnegie China.