Japan

• Myoko
  Japanese cruiser Myoko
  was the name-ship of the four-member of heavy cruisers of the Imperial Japanese Navy — the other ships of the class being the Nachi, Ashigara, and Haguro....
  
  (5th Fleet flag ship) - Vice Admiral Kondo Nobutake
• Nagara
  Japanese cruiser Nagara
  was the lead ship of her class of light cruiser in the Imperial Japanese Navy. She was named after the Nagara River in the Chūbu region of Japan.-Background:...
  
  
• Natori
  Japanese cruiser Natori
  was a Nagara-class light cruiser in the Imperial Japanese Navy. It was named after the Natori River in Miyagi prefecture, Japan.-Background:Natori was the fourth vessel completed in the Nagara-class of light cruisers...
  
  
• 23rd Destroyer Group
  • Mochizuki
    Japanese destroyer Mochizuki
    was one of twelve destroyers, built for the Imperial Japanese Navy following World War I. Advanced for their time, these ships served as first-line destroyers through the 1930s, but were considered obsolescent by the start of the Pacific War...
    
    , Mutsuki
    Japanese destroyer Mutsuki
    was the lead ship of twelve destroyers, built for the Imperial Japanese Navy following World War I. Advanced for their time, these ships served as first-line destroyers through the 1930s, but were considered obsolescent by the start of the Pacific War.-History:...
    
    , Mikazuki, Kikuzuki
• 45th Destroyer Group
  • Matsukaze, Asakaze
• 28th Destroyer Group
  • Yūnagi
    Japanese destroyer Yunagi (1924)
    was the ninth and final vessel of the Kamikaze-class destroyers built for the Imperial Japanese Navy following World War I. Advanced for their time, these ships served as first-line destroyers through the 1930s, but were considered obsolescent by the start of the Pacific War.-History:Construction...
    
    , Asanagi
    Japanese destroyer Asanagi
    was the eighth vessel of the Kamikaze-class destroyers built for the Imperial Japanese Navy following World War I. Advanced for their time, these ships served as first-line destroyers through the 1930s, but were considered obsolescent by the start of the Pacific War.-History:Construction of the...
    
    
• 12th Minesweeper Group
• 1st Air Sentai
  • Akagi
    Japanese aircraft carrier Akagi
    Akagi was an aircraft carrier of the Imperial Japanese Navy , originally begun as an . She was converted while still under construction to an aircraft carrier under the terms of the Washington Naval Treaty...
    
    , Chiyoda
    Japanese aircraft carrier Chiyoda
    was an Chitose class aircraft carrier of the Imperial Japanese Navy. She was originally built as a seaplane carrier, before being converted to a light carrier from March to December 1943.She was damaged in the Battle of the Philippine Sea....
    
    
• 1st Air Unit
  • 14th Kokutai
  • 16th Kokutai
• 4th Base Force
  • Yokosuka 4th SNLF
  • Kure 6th SNLF
  • Sasebo 8th SNLF
• 5th Garrison Unit
• Taiwan Mixed Brigade - (Major Gen. Iida)
  • Taiwan 1st Infantry Regiment
  • Taiwan 2nd Infantry Regiment
  • Taiwan Mountain Gun Regiment

China

• 5th Security Brigade - Wang Yi
  • 2 Security Regiments - About 1,600 men
  • 7 Guard Battalions (Newly formed from residents) - 1,750 men
• Communist Independent Battalion - 300 men
• Xiuying Battery Garrisons (Still undergoing organization) - 250 men

Sources

• 中国抗日战争正面战场作战记 China's Anti-Japanese War Combat Operations
  • Author : Guo Rugui, editor-in-chief Huang Yuzhang
  • Press : Jiangsu People's Publishing House
  • Date published : 2005-7-1
  • ISBN 7-214-03034-9
  • Online in Chinese http://www.wehoo.net/book/wlwh/a30012/A0170.htm#
    • 第七部分：相持阶段前期的作战海南岛作战 1 Hainan Island battles