diff --git a/openstack/identity/v2/tenants/requests.go b/openstack/identity/v2/tenants/requests.go
index a08980df2c..84a8b9df1d 100644
--- a/openstack/identity/v2/tenants/requests.go
+++ b/openstack/identity/v2/tenants/requests.go
@@ -7,6 +7,12 @@ import (
 	"github.com/gophercloud/gophercloud/v2/pagination"
 )
 
+// ListOptsBuilder allows extensions to add additional parameters to the
+// List request.
+type ListOptsBuilder interface {
+	ToTenantListQuery() (string, error)
+}
+
 // ListOpts filters the Tenants that are returned by the List call.
 type ListOpts struct {
 	// Marker is the ID of the last Tenant on the previous page.
@@ -16,15 +22,21 @@ type ListOpts struct {
 	Limit int `q:"limit"`
 }
 
+// ToTenantListQuery formats a ListOpts into a query string.
+func (opts ListOpts) ToTenantListQuery() (string, error) {
+	q, err := gophercloud.BuildQueryString(opts)
+	return q.String(), err
+}
+
 // List enumerates the Tenants to which the current token has access.
-func List(client *gophercloud.ServiceClient, opts *ListOpts) pagination.Pager {
+func List(client *gophercloud.ServiceClient, opts ListOptsBuilder) pagination.Pager {
 	url := listURL(client)
 	if opts != nil {
-		q, err := gophercloud.BuildQueryString(opts)
+		query, err := opts.ToTenantListQuery()
 		if err != nil {
 			return pagination.Pager{Err: err}
 		}
-		url += q.String()
+		url += query
 	}
 	return pagination.NewPager(client, url, func(r pagination.PageResult) pagination.Page {
 		return TenantPage{pagination.LinkedPageBase{PageResult: r}}
diff --git a/openstack/networking/v2/extensions/layer3/routers/requests.go b/openstack/networking/v2/extensions/layer3/routers/requests.go
index 5d31ec1138..def4699db3 100644
--- a/openstack/networking/v2/extensions/layer3/routers/requests.go
+++ b/openstack/networking/v2/extensions/layer3/routers/requests.go
@@ -55,12 +55,15 @@ func (opts ListOpts) ToRouterListQuery() (string, error) {
 // Default policy settings return only those routers that are owned by the
 // tenant who submits the request, unless an admin user submits the request.
 func List(c *gophercloud.ServiceClient, opts ListOptsBuilder) pagination.Pager {
-	q, err := opts.ToRouterListQuery()
-	if err != nil {
-		return pagination.Pager{Err: err}
+	url := rootURL(c)
+	if opts != nil {
+		query, err := opts.ToRouterListQuery()
+		if err != nil {
+			return pagination.Pager{Err: err}
+		}
+		url += query
 	}
-	u := rootURL(c) + q
-	return pagination.NewPager(c, u, func(r pagination.PageResult) pagination.Page {
+	return pagination.NewPager(c, url, func(r pagination.PageResult) pagination.Page {
 		return RouterPage{pagination.LinkedPageBase{PageResult: r}}
 	})
 }
diff --git a/openstack/networking/v2/extensions/security/rules/requests.go b/openstack/networking/v2/extensions/security/rules/requests.go
index 405cf549ca..a3c6a8a2e0 100644
--- a/openstack/networking/v2/extensions/security/rules/requests.go
+++ b/openstack/networking/v2/extensions/security/rules/requests.go
@@ -51,12 +51,15 @@ func (opts ListOpts) ToSecGroupListQuery() (string, error) {
 // security group rules. It accepts a ListOpts struct, which allows you to filter
 // and sort the returned collection for greater efficiency.
 func List(c *gophercloud.ServiceClient, opts ListOptsBuilder) pagination.Pager {
-	q, err := opts.ToSecGroupListQuery()
-	if err != nil {
-		return pagination.Pager{Err: err}
+	url := rootURL(c)
+	if opts != nil {
+		query, err := opts.ToSecGroupListQuery()
+		if err != nil {
+			return pagination.Pager{Err: err}
+		}
+		url += query
 	}
-	u := rootURL(c) + q
-	return pagination.NewPager(c, u, func(r pagination.PageResult) pagination.Page {
+	return pagination.NewPager(c, url, func(r pagination.PageResult) pagination.Page {
 		return SecGroupRulePage{pagination.LinkedPageBase{PageResult: r}}
 	})
 }