diff --git a/charts/kube-prometheus-stack/templates/alertmanager/ingress.yaml b/charts/kube-prometheus-stack/templates/alertmanager/ingress.yaml
index be9f5aa279c4..c4b8da62e412 100644
--- a/charts/kube-prometheus-stack/templates/alertmanager/ingress.yaml
+++ b/charts/kube-prometheus-stack/templates/alertmanager/ingress.yaml
@@ -1,5 +1,5 @@
 {{- if and .Values.alertmanager.enabled .Values.alertmanager.ingress.enabled }}
-{{- $pathType := .Values.alertmanager.ingress.pathType | default "ImplementationSpecific" }}
+{{- $pathType := .Values.alertmanager.ingress.pathType | default "Prefix" }}
 {{- $serviceName := printf "%s-%s" (include "kube-prometheus-stack.fullname" .) "alertmanager" }}
 {{- $backendServiceName := .Values.alertmanager.ingress.serviceName | default (printf "%s-%s" (include "kube-prometheus-stack.fullname" .) "alertmanager") }}
 {{- $servicePort := .Values.alertmanager.ingress.servicePort | default .Values.alertmanager.service.port -}}