diff --git a/ext/debug/debug.c b/ext/debug/debug.c
index b27263d46..e1ae28148 100644
--- a/ext/debug/debug.c
+++ b/ext/debug/debug.c
@@ -56,15 +56,23 @@ static VALUE
 di_body(const rb_debug_inspector_t *dc, void *ptr)
 {
     VALUE skip_path_prefix = (VALUE)ptr;
+#if defined(HAVE_RB_DEBUG_INSPECTOR_FRAME_COUNT) && defined(HAVE_RB_DEBUG_INSPECTOR_FRAME_LOC_GET)
+    long len = rb_debug_inspector_frame_count(dc);
+#else
     VALUE locs = rb_debug_inspector_backtrace_locations(dc);
-    VALUE ary = rb_ary_new();
     long len = RARRAY_LEN(locs);
+#endif
+    VALUE ary = rb_ary_new();
     long i;
 
     for (i=1; i<len; i++) {
         VALUE e;
         VALUE iseq = rb_debug_inspector_frame_iseq_get(dc, i);
+#if defined(HAVE_RB_DEBUG_INSPECTOR_FRAME_COUNT) && defined(HAVE_RB_DEBUG_INSPECTOR_FRAME_LOC_GET)
+        VALUE loc = rb_debug_inspector_frame_loc_get(dc, i);
+#else
         VALUE loc = RARRAY_AREF(locs, i);
+#endif
         VALUE path;
 
         if (!NIL_P(iseq)) {
diff --git a/ext/debug/extconf.rb b/ext/debug/extconf.rb
index 9c4f5417a..26804fbd3 100644
--- a/ext/debug/extconf.rb
+++ b/ext/debug/extconf.rb
@@ -7,6 +7,8 @@
   $defs << '-DHAVE_RB_ISEQ'
   $defs << '-DHAVE_RB_ISEQ_PARAMETERS'
   $defs << '-DHAVE_RB_ISEQ_CODE_LOCATION'
+  $defs << '-DHAVE_RB_DEBUG_INSPECTOR_FRAME_COUNT'
+  $defs << '-DHAVE_RB_DEBUG_INSPECTOR_FRAME_LOC_GET'
 
   if RUBY_VERSION >= '3.1.0'
     $defs << '-DHAVE_RB_ISEQ_TYPE'
@@ -22,6 +24,11 @@
   # from Ruby 3.1
   have_func "rb_iseq_type(NULL)",
             [["VALUE rb_iseq_type(void *);"]]
+  # from Ruby 3.5
+  have_func "rb_debug_inspector_frame_count(NULL)",
+            [["VALUE rb_debug_inspector_frame_count(void *);"]]
+  have_func "rb_debug_inspector_frame_loc_get(NULL, 0)",
+            [["VALUE rb_debug_inspector_frame_loc_get(void *, int index);"]]
 end
 
 create_makefile 'debug/debug'
diff --git a/test/console/nested_break_test.rb b/test/console/nested_break_test.rb
index d7e2437e5..f038d0fa6 100644
--- a/test/console/nested_break_test.rb
+++ b/test/console/nested_break_test.rb
@@ -83,7 +83,7 @@ def test_multiple_nested_break
           assert_line_num 2
           type 'p foo(142)'
           type 'bt'
-          assert_line_text(/\#7\s+<main>/) # TODO: can be changed
+          assert_line_text(/\#11\s+<main>/) # TODO: can be changed
 
           type 'c'
           assert_line_text(/143/)
diff --git a/test/console/trap_test.rb b/test/console/trap_test.rb
index 17c4ccfa7..0f18e14ac 100644
--- a/test/console/trap_test.rb
+++ b/test/console/trap_test.rb
@@ -16,7 +16,6 @@ def test_sigint
       debug_code program, remote: false do
         type 'b 3'
         type 'c'
-        assert_line_num 2
         assert_line_text(/is registered as SIGINT handler/)
         type 'sigint'
         assert_line_num 3