diff --git a/.changelog/3742.txt b/.changelog/3742.txt
new file mode 100644
index 00000000000..0395042d07d
--- /dev/null
+++ b/.changelog/3742.txt
@@ -0,0 +1,3 @@
+```release-note:bug
+certificate_authorities: fixes for methods to interact with Certificate Authorities Hostname Associations API
+```
\ No newline at end of file
diff --git a/certificate_authorities.go b/certificate_authorities.go
index b9cffb2ab61..80ba39c877f 100644
--- a/certificate_authorities.go
+++ b/certificate_authorities.go
@@ -17,9 +17,18 @@ type UpdateCertificateAuthoritiesHostnameAssociationsParams struct {
 	MTLSCertificateID string                `json:"mtls_certificate_id,omitempty"`
 }
 
+type HostnameAssociationsUpdateRequest struct {
+	Hostnames         []HostnameAssociation `json:"hostnames,omitempty"`
+	MTLSCertificateID string                `json:"mtls_certificate_id,omitempty"`
+}
+
 type HostnameAssociationsResponse struct {
 	Response
-	Result []HostnameAssociation `json:"result"`
+	Result HostnameAssociations `json:"result"`
+}
+
+type HostnameAssociations struct {
+	Hostnames []HostnameAssociation `json:"hostnames"`
 }
 
 type HostnameAssociation = string
@@ -28,12 +37,11 @@ type HostnameAssociation = string
 //
 // API Reference: https://developers.cloudflare.com/api/resources/certificate_authorities/subresources/hostname_associations/methods/get/
 func (api *API) ListCertificateAuthoritiesHostnameAssociations(ctx context.Context, rc *ResourceContainer, params ListCertificateAuthoritiesHostnameAssociationsParams) ([]HostnameAssociation, error) {
+	if rc.Level != ZoneRouteLevel {
+		return []HostnameAssociation{}, ErrRequiredZoneLevelResourceContainer
+	}
 
-	uri := fmt.Sprintf(
-		"/%s/%s/certificate_authorities/hostname_associations",
-		rc.Level,
-		rc.Identifier,
-	)
+	uri := buildURI(fmt.Sprintf("/zones/%s/certificate_authorities/hostname_associations", rc.Identifier), params)
 
 	res, err := api.makeRequestContext(ctx, http.MethodGet, uri, nil)
 	if err != nil {
@@ -46,18 +54,18 @@ func (api *API) ListCertificateAuthoritiesHostnameAssociations(ctx context.Conte
 		return []HostnameAssociation{}, fmt.Errorf("%s: %w", errUnmarshalError, err)
 	}
 
-	return hostnameAssociationsResponse.Result, nil
+	return hostnameAssociationsResponse.Result.Hostnames, nil
 }
 
 // Replace Hostname Associations
 //
 // API Reference: https://developers.cloudflare.com/api/resources/certificate_authorities/subresources/hostname_associations/methods/update/
 func (api *API) UpdateCertificateAuthoritiesHostnameAssociations(ctx context.Context, rc *ResourceContainer, params UpdateCertificateAuthoritiesHostnameAssociationsParams) ([]HostnameAssociation, error) {
-	uri := fmt.Sprintf(
-		"/%s/%s/certificate_authorities/hostname_associations",
-		rc.Level,
-		rc.Identifier,
-	)
+	if rc.Level != ZoneRouteLevel {
+		return []HostnameAssociation{}, ErrRequiredZoneLevelResourceContainer
+	}
+	
+	uri := fmt.Sprintf("/zones/%s/certificate_authorities/hostname_associations", rc.Identifier)
 
 	res, err := api.makeRequestContext(ctx, http.MethodPut, uri, params)
 	if err != nil {
@@ -70,5 +78,5 @@ func (api *API) UpdateCertificateAuthoritiesHostnameAssociations(ctx context.Con
 		return []HostnameAssociation{}, fmt.Errorf("%s: %w", errUnmarshalError, err)
 	}
 
-	return hostnameAssociationsResponse.Result, nil
+	return hostnameAssociationsResponse.Result.Hostnames, nil
 }
diff --git a/certificate_authorities_test.go b/certificate_authorities_test.go
index 940524a5b7b..cba5c57f7a2 100644
--- a/certificate_authorities_test.go
+++ b/certificate_authorities_test.go
@@ -6,6 +6,7 @@ import (
 	"net/http"
 	"testing"
 
+	"github.com/goccy/go-json"
 	"github.com/stretchr/testify/assert"
 )
 
@@ -15,15 +16,18 @@ func TestListCertificateAuthoritiesHostnameAssociations(t *testing.T) {
 
 	handler := func(w http.ResponseWriter, r *http.Request) {
 		assert.Equal(t, http.MethodGet, r.Method, "Expected method 'GET', got %s", r.Method)
+		assert.Equal(t, "72ef4d06-4752-4493-a60a-7421470fd585", r.URL.Query().Get("mtls_certificate_id"))
 		w.Header().Set("content-type", "application/json")
 		fmt.Fprintf(w, `{
 			"success": true,
 			"errors": [],
 			"messages": [],
-			"result": [
-				"admin.example.com",
-				"foobar.example.com"
-			]
+			"result": {
+				"hostnames": [
+					"admin.example.com",
+					"foobar.example.com"
+				]
+			}
 		}`)
 	}
 
@@ -51,19 +55,32 @@ func TestUpdateCertificateAuthoritiesHostnameAssociations(t *testing.T) {
 
 	handler := func(w http.ResponseWriter, r *http.Request) {
 		assert.Equal(t, http.MethodPut, r.Method, "Expected method 'PUT', got %s", r.Method)
+
+		wantReqHostnames := []HostnameAssociation{
+			"admin.example.com",
+			"foobar.example.com",
+		}
+		var req HostnameAssociationsUpdateRequest
+		assert.NoError(t, json.NewDecoder(r.Body).Decode(&req))
+		assert.Equal(t, "72ef4d06-4752-4493-a60a-7421470fd585", req.MTLSCertificateID)
+		assert.Equal(t, wantReqHostnames, req.Hostnames)
+
 		w.Header().Set("content-type", "application/json")
 		fmt.Fprintf(w, `{
 			"success": true,
 			"errors": [],
 			"messages": [],
-			"result": [
-				"admin.example.com",
-				"foobar.example.com"
-			]
+			"result": {
+				"hostnames": [
+					"admin.example.com",
+					"foobar.example.com"
+				]
+			}
 		}`)
 	}
 
 	hostnameAssociations := UpdateCertificateAuthoritiesHostnameAssociationsParams{
+		MTLSCertificateID: "72ef4d06-4752-4493-a60a-7421470fd585",
 		Hostnames: []HostnameAssociation{
 			"admin.example.com",
 			"foobar.example.com",