Answer

Thank you for your question.

No, it is not permissible for a woman to wear sandals and show her feet when she goes outside, nor during the prayer.

In the Shafi’i school, feet are considered part of her nakedness and must be covered.

Please find more details here:
Women Covering Feet

May Allah give you the best of this world and the next.
[Ustadha] Shazia Ahmad
Checked and Approved by Shaykh Faraz Rabbani

Ustadha Shazia Ahmad lived in Damascus, Syria for two years where she studied aqidah, fiqh, tajweed, tafsir, and Arabic. She then attended the University of Texas at Austin, where she completed her Masters in Arabic. Afterward, she moved to Amman, Jordan where she studied fiqh, Arabic, and other sciences. She later moved back to Mississauga, Canada, where she lives with her family.