Isobelle is a moderately popular girls' name in England & Wales, ranking #265 in 2009 with 181 recorded births. The name reached its all-time peak in 2009 with 181 births ranking #265. Since 1996, the popularity has increased by 311.4%. In 2009, approximately 1 in every 1,731 girls born was named Isobelle. FALLING Recent data shows the name is currently falling.