Isabel Alfonsa married her first cousin once removed Count Jan Kanty Zamoyski, seventh child and third son of Count Andrzej Zamoyski and his wife Princess Maria Carolina of Bourbon-Two Sicilies, on 9 March 1929 in Madrid.
Isabel Alfonsa and Jan had four children: 
Count Karol Alfons Zamoyski (28 October 1930 – 26 October 1979)
Countess Maria Krystyna Zamoyska (2 September 1932 – 6 December 1959)
Count Józef Michal Zamoyski (born 27 June 1935-22/23 May 2010)
Countess Maria Teresa Zamoyska (born 18 April 1938)
Isabel Alfonsa married her first cousin once removed Count Jan Kanty Zamoyski, seventh child and third son of Count Andrzej Zamoyski and his wife Princess Maria Carolina of Bourbon-Two Sicilies, on 9 March 1929 in Madrid. Isabel Alfonsa and Jan had four children: 
Count Karol Alfons Zamoyski (28 October 1930 – 26 October 1979)
Countess Maria Krystyna Zamoyska (2 September 1932 – 6 December 1959)
Count Józef Michal Zamoyski (born 27 June 1935-22/23 May 2010)
Countess Maria Teresa Zamoyska (born 18 April 1938)
Princess Isabel Alfonsa of Bourbon-Two Sicilies