Royal Netherlands Navy
Dornier Do-24 K
Starting in the late 1930s, the Dornier Do.24K was the principal reconnaissance aircraft of the Netherlands Navy in the Netherlands East Indies. This extensive site details the aircraft's service history for different counties.
This site contains a lot of information about current and historical warhips of many navies, including the Dutch Navy.
United 'Netherlands Navy & Maritime Forum
This forum deals with all subjects related to the Dutch and the sea. It is visited by former servicemen, historians and relatives. The subjects range from current politcs and policy to historical battles and warships.
The Story of a Twentieth Century Englishman: Witness to a passing age
By Brian Smith. The website is a biography of Mr. Ralph M. Smith OBE, who served on board the Dutch sloop Flores as coder between 1943-1944.
Dutch merchant navy
Nederlandse koopvaardij 1940-1946 (Excellent site about the Dutch merchant navy during W.W.2
MS Abbekerk: the story of a Dutch freighter during the Second World War
The Abbekerk was a 7900-gross tons freighter, completed in 1939 for the shipping company V.N.S. The ship saw a lot of action in the war, reinforcing Singapore and evacuating Allied troops and civilians from Java in early 1942. She was lost to a U-boat torpedo in August 1942. The author of this website details the history of the ship and his father, who was part of the engine room staff during the war.
The unofficial Holland America Line Home Page (with info and pics of their ships)
This website is dedicated to the complex history of the Nederlandsche Dok en Scheepsbouw Maatschappij (NDSM) and its legal predecessors, the N.V. Nederlandsche Scheepsbouw Maatschappij (NSM) and the N.V. Nederlandsche Dok Maatschappij (NDM). These dockyards were mainly involved in building merchant ships, but just before and during World War II, the NSM also built a number of warships. Two of them were the flotilla leaders Tromp and Jacob van Heemskerck. The website goes into detail about the companies' histories, the ships they built and the men who built them.
Other Dutch military links
Grebbeberg.nl (Excellent site about the fighting in this area in May 1940)
Go2war2.nl (new Dutch site about World War II)
Defensieforum.nl (The place for discussions about the Dutch armed forces)
Overvalwagens! (Dutch armoured vehicles in the Dutch East and West Indies)
Onderscheidingen forum (brandnew forum where you can discuss Dutch military decorations and awards)
Royal Dutch Army Order of Battle - May 10th, 1940
Overview of all units and their armaments. What I like about this site is that it's well-researched and to the point: no flashy images or any of that to distract you from what the site is all about.
Dutch official sites
The Dutch ministry of Defense homepage (official site of the Dutch ministry of Defence)
Marinemuseum Den Helder (official museum of the Royal Netherlands Navy)
Nederlands Instituut voor Oorlogsdocumentatie (Netherlands Institute for War Documentation)
Dutch veteran and personnel sites
Koninklijke Vereniging van Marineofficieren (nice site for and from Dutch naval officers)
Veteranen Online (home for many veterans)
Joop Westerhof in the N.E.I. 1947-1950 (the personal story of one of many Dutch soldiers in the N.E.I. 1945-1950)
Kriegsmarine (German navy)
Werkgroep Kriegsmarine is an association of Dutch naval historians en enthousiasts, with a focus on the history of the Kriegsmarine and its link to the Netherlands during 1940-1945
Kriegsmarine Encyclopedia (By Michael Emmerich)
Chronik 1939-45 (a transcription of Hümmelchen and Rohwer's famous naval chronology)
Prinzeugen.com (Kriegsmarine Online Photo Archive. Many rare photos)
Uboat.net (THE site on the subject)
The U-boat archive (Many photos, by Jerry Mason)
The Battleship Bismarck (leading site on this ship)
The history of Bismarck and Tirpitz (by John Rasmussen)
The history of Scharnhorst and Gneisenau (another excellent site by John Rasmussen)
USS Erie (PG-50) (brand new site about this gunboat by Jon Balson)
The Hyperwar project (Everything you need on the US armed forces in WW2)
Nihon Kaigun (highly recommended. Check out the articles)
Marine Archiv - das Forum für Historiker, Schiffsfreunde und Modellbauer (forum which covers all major navies, both in the first and second world war. In German)
J-Aircraft.org (highly recommended, mainly for Japanese aircraft, ships and operations)
Pacific War 1941-1945 forum (forum which belongs to this site)
Commonwealth navies (including the merchant navy)
Extensive resource on the history of the Royal Navy during World War I and World War II. The site contains an extensive chronology of the war at sea, seen from the British perspective. There is also an extensive list of service histories of Royal Navy warships. Highly recommended!
World War II Cruiser Operarations (excellent site)
HMS Hood organization (the official site of this giant)
RMS Empress of Asia (The history of this British liner sunk off Singapore in February 1942)
Naval-History.net (extensive resource with RN day-to-day histories of ships, Admiralty War Diaries, casualties etc.)
Royal Navy Flag Officers 1904-1945 (extensive resource on these men)
Norwegian Merchant Fleet 1939-1945 (Excellent site by Siri Lawson)
Regiamarina.net (excellent site about the Italian Navy)