British's navy's biggest ship HMS Ocean will be moored in the Thames river while Typhoon fighter jets will provide air cover, Sky News reported.
The security measures have led to the costs of the games spiralling to around one billion pounds (around $1.55 billion).
Defence Secretary Philip Hammond said around 7,500 personnel would be dedicated to venue security.
Along with the HMS Ocean, the HMS Bulwark assault ship will carry Puma or Lynx choppers or even Apache attack helicopters, the report said.
There would be 1,000 "unarmed" personnel plus 12,000 policemen.
The Special Air Service and the Special Boat Service -- special forces units -- will be on standby to react to any terrorist incident, and will be based in "secret locations" in London.
Originally, the security budget was set at 600 million pounds with a 238 million-pound contingency fund.
Recently, the government announced that an extra 270 million pounds was being set aside for Olympic venue security from its total budget of 9.3 billion pounds.