French submarine Gustave Zédé the largest in in the world according to the Dutch magazine Marineblad dated 1913-1914 no. 5

Largest Dutch submarine Hr. Ms. K-I

An item reported that the Gustave Zédé (1) was the largest submarine in the world at that moment being completed. She measured 800 (surfaced)-1.100 (submerged) tons and a speed of 20 (surfaced)-10 (submerged) miles.(2)

Note
1. The Q2. Building ordered on 4 October 1890, laid down as Sirène at Toulon, France on 1 February 1891, renamed Gustave Zéd on 1 May 1891, launched on  June 1893, commissioned on 1 May 1900, decommissioned on 9 August 1908 and sold to be broken up on 2 August 1911.
2. The Netherlands were building at the same time an ocean going submarine Hr. Ms. K I with a displacement of just 333 (surfaced)-358 (submerged) tons and a speed of 17 (surfaced)-8 (submerged) knots. Laid down at Kon. Mij. De Schelde, Vlissingen, Netherlands on 16 September 1911, launched on 20 May 1913, commissioned on 5 July 1914 and decommissioned in 1829. She served in the Dutch East Indies. Her submarine Hr. Ms. O-2 who served in European (coastal) waters had a displacement of just 134 (surfaced)-149 (submerged) tons and was built between 1909-1911.