The gulden was the currency of the Free City of Danzig between 1923 and 1939. It was divided into 100 pfennige.
Until 1923, Danzig used the German papiermark and issued several local 'emergency notes'. Inflation during 1922–23 averaged roughly 2440% per month. In July 1923 it was announced that a new and independent currency (the gulden) was being established with the approval of the League of Nations finance committee to replace the German mark. The gulden was introduced at a value of 25 gulden = 1 pound sterling.
Danzig was annexed by Nazi Germany on 1 September 1939, the day the invasion of Poland had begun. On the same day reichsmark coins and notes were declared legal tender alongside the Danzig gulden, with 1 gulden being equal to 0.70 reichsmark. This was a favourable exchange rate for inhabitants of Danzig, since the actual exchange rate was around 0.47 reichsmark per gulden. To prevent abuse on 7 September the import of gulden coins and notes into the territory of the former free city was prohibited. Bank assets were however converted at the market rate of 0.47 reichsmark per gulden.
With effect on 7 September 1939, coins of 1 and 2 pfennige became legal tender throughout Nazi Germany as 1 and 2 reichspfennige, and would remain in circulation until November 1940. On 30 September the reichsmark became the sole currency on the territory of the former free city. Notes and coins of 5 and 10 gulden were withdrawn that day and could be exchanged for reichsmarks until 15 October. Coins of 5 and 10 pfennig and 1⁄2 and 1 gulden remained in circulation until 25 June 1940 and were redeemed until 25 July.