Across Four Oceans is a free rules set for use with World War II era miniatures. The base rules are tactical, but there is also an operational game that features secret objectives. The rules can simulate almost any kind of encounter, varying from carrier clashes to convoy battles. There is no tape measuring required. Instead, the players move and fight on a hexagonal map. All ship statistics have been simplified, and the system uses only six-sided dice.

All of the rules and navy lists can be found in the files sections. Navy lists include ships, aircraft, bases, and special rules. Operational maps can be downloaded in both the files section and under the web links. Future maps covering the Arctic and Indian Ocean will be available in the future.

The following navies are represented in the game: America, Argentina, Australia, Brazil, Britain, Canada, Chile, China, Colombia, Denmark, Finland, France, Germany, Greece, Italy, Japan, Mexico, Netherlands, New Zealand, Norway, Peru, Poland, Portugal, Romania, Soviet Union, Spain, Sweden, Thailand, Turkey, and Yugoslavia.

Also, for fun there are hypothetical navies for the Confederate States of America and the Austro-Hungarian Empire.