The other primary element of their diet are web-building spiders, which make up an increased portion of their prey in areas where suitable flies are absent.

Most spiders consumed by Geoffroy's bats are of the family Araneidae, with a secondary presence of Theridiidae species.

[3] In Southern Basque Country, colonies of Geoffroy's bats feed on a diversity of arthropods during the beginning of the breeding season, with flies making up the largest grouping of prey.

[3] Iberian populations of Geoffroy's bat forage mainly in broad-leaved and mixed forests, and less commonly in coniferous plantations.

[1] Geoffroy's bat can be found in Afghanistan, Albania, Algeria, Andorra, Armenia, Austria, Azerbaijan, Belgium, Bosnia and Herzegovina, Bulgaria, Croatia, Cyprus, Czech Republic, France, Georgia, Germany, Greece, Hungary, Iran, Israel, Italy, Jordan, Kazakhstan, Kyrgyzstan, Lebanon, Luxembourg, Montenegro, Morocco, Netherlands, North Macedonia, Oman, Poland, Portugal, Romania, Russian Federation, San Marino, Saudi Arabia, Serbia, Slovakia, Slovenia, Spain, Switzerland, Tajikistan, Tunisia, Turkey, Turkmenistan, Ukraine, and Uzbekistan.

[3] Iberian colonies are instead dependent on complex, heterogenous forest habitats, which favor the proliferation of spider prey.