diff --git a/Cargo.lock b/Cargo.lock
index 6ebfcfcb3db76..528e4490594b4 100644
--- a/Cargo.lock
+++ b/Cargo.lock
@@ -2264,6 +2264,7 @@ name = "oxc_regular_expression"
 version = "0.103.0"
 dependencies = [
  "bitflags",
+ "insta",
  "oxc_allocator",
  "oxc_ast_macros",
  "oxc_diagnostics",
diff --git a/crates/oxc_regular_expression/Cargo.toml b/crates/oxc_regular_expression/Cargo.toml
index aa6e521f8bfce..aaad064403ce7 100644
--- a/crates/oxc_regular_expression/Cargo.toml
+++ b/crates/oxc_regular_expression/Cargo.toml
@@ -30,5 +30,8 @@ phf = { workspace = true, features = ["macros"] }
 rustc-hash = { workspace = true }
 unicode-id-start = { workspace = true }
 
+[dev-dependencies]
+insta = { workspace = true }
+
 [package.metadata.cargo-shear]
 ignored-paths = ["src/generated/derive_get_address.rs"]
diff --git a/crates/oxc_regular_expression/tests/diagnostics.rs b/crates/oxc_regular_expression/tests/diagnostics.rs
new file mode 100644
index 0000000000000..ec63066ece1a9
--- /dev/null
+++ b/crates/oxc_regular_expression/tests/diagnostics.rs
@@ -0,0 +1,95 @@
+//! Snapshot tests for regex parse error diagnostics.
+//!
+//! Each test case triggers one specific error type to verify
+//! that error messages and help text are correct.
+
+use oxc_allocator::Allocator;
+use oxc_diagnostics::{GraphicalReportHandler, GraphicalTheme, NamedSource};
+use oxc_regular_expression::{LiteralParser, Options};
+use std::fmt::Write;
+
+fn test_err(allocator: &Allocator, pattern: &str, flags: Option<&str>) -> String {
+    let source = format!("/{pattern}/{}", flags.unwrap_or(""));
+    let err = LiteralParser::new(
+        allocator,
+        pattern,
+        flags,
+        Options {
+            pattern_span_offset: 1,
+            flags_span_offset: u32::try_from(pattern.len()).unwrap() + 2,
+        },
+    )
+    .parse()
+    .expect_err(&format!("{source} should fail to parse"));
+
+    let error = err.with_source_code(NamedSource::new(source.clone(), source));
+    let handler = GraphicalReportHandler::new_themed(GraphicalTheme::unicode_nocolor());
+    let mut output = String::new();
+    handler.render_report(&mut output, error.as_ref()).unwrap();
+    output
+}
+
+#[test]
+fn test() {
+    let allocator = Allocator::default();
+
+    let cases: &[(&str, Option<&str>, &str)] = &[
+        // Flag errors
+        ("a", Some("z"), "unknown_flag"),
+        ("a", Some("gg"), "duplicated_flags"),
+        ("a", Some("uv"), "invalid_unicode_flags"),
+        // Capturing group errors
+        (r"(?<n>.)(?<n>.)", Some(""), "duplicated_capturing_group_names"),
+        (r"(?<>a)", Some(""), "empty_group_specifier"),
+        // Quantifier errors
+        ("+", Some("u"), "lone_quantifier"),
+        ("a|+", Some(""), "invalid_braced_quantifier"),
+        ("a{", Some("u"), "invalid_braced_quantifier_unicode"),
+        (
+            r"x{99999999999999999999999999999999999999999999999999}",
+            Some(""),
+            "too_large_number_in_braced_quantifier",
+        ),
+        (r"a{2,1}", Some(""), "braced_quantifier_out_of_order"),
+        // Unterminated patterns
+        ("(", Some(""), "unterminated_group"),
+        ("[", Some(""), "unterminated_character_class"),
+        // Reference errors
+        (r"\1", Some("u"), "invalid_indexed_reference"),
+        (r"\k<a>", Some("u"), "invalid_named_reference"),
+        // Unicode property errors
+        (r"\P{Basic_Emoji}", Some("v"), "invalid_unicode_property_name_negative_strings"),
+        (r"\p{Basic_Emoji}", Some("u"), "invalid_unicode_property_of_strings"),
+        (r"\p{Foo}", Some("u"), "invalid_unicode_property"),
+        // Character class errors
+        ("[z-a]", Some(""), "character_class_range_out_of_order"),
+        (r"[\d-z]", Some("u"), "character_class_range_invalid_atom"),
+        (r"[a-\d]", Some("u"), "invalid_class_atom"),
+        // Unicode sets mode (v flag) errors
+        (r"[&&]", Some("v"), "empty_class_set_expression"),
+        (r"[a&&&b]", Some("v"), "class_intersection_unexpected_ampersand"),
+        (r"[a&&]", Some("v"), "class_set_expression_invalid_character"),
+        (r"[a&&b(]", Some("v"), "class_set_expression_invalid_character"),
+        (r"[[^\q{ng}]]", Some("v"), "character_class_contents_invalid_operands"),
+        // Unicode escape errors
+        (r"\u{FFFFFFFFFFFFFFFFFFFFFFFFFFFFFFF}", Some("u"), "too_large_number_digits"),
+        (r"\ua", Some("u"), "invalid_unicode_escape_sequence"),
+        (r"\u{110000}", Some("u"), "invalid_surrogate_pair"),
+        // Escape errors
+        (r"\c0", Some("u"), "invalid_extended_atom_escape"),
+        // Modifier errors
+        (r"(?ii:.)", Some(""), "invalid_modifiers"),
+        (r"(?a:.)", Some(""), "unknown_modifiers"),
+        // Parse errors
+        (")", Some("v"), "parse_pattern_incomplete"),
+    ];
+
+    let mut snapshot = String::new();
+    for (pattern, flags, name) in cases {
+        writeln!(snapshot, "# {name}").unwrap();
+        snapshot.push_str(&test_err(&allocator, pattern, *flags));
+        snapshot.push('\n');
+    }
+
+    insta::assert_snapshot!(snapshot);
+}
diff --git a/crates/oxc_regular_expression/tests/snapshots/diagnostics__test.snap b/crates/oxc_regular_expression/tests/snapshots/diagnostics__test.snap
new file mode 100644
index 0000000000000..d42c8d779fe10
--- /dev/null
+++ b/crates/oxc_regular_expression/tests/snapshots/diagnostics__test.snap
@@ -0,0 +1,260 @@
+---
+source: crates/oxc_regular_expression/tests/diagnostics.rs
+expression: snapshot
+---
+# unknown_flag
+
+  × Invalid regular expression: Unknown flag: `z` found
+   ╭─[/a/z:1:4]
+ 1 │ /a/z
+   ·    ─
+   ╰────
+
+# duplicated_flags
+
+  × Invalid regular expression: Duplicated flag: `g` found
+   ╭─[/a/gg:1:5]
+ 1 │ /a/gg
+   ·     ─
+   ╰────
+
+# invalid_unicode_flags
+
+  × Invalid regular expression: Invalid unicode flags combination `u` and `v`
+   ╭─[/a/uv:1:5]
+ 1 │ /a/uv
+   ·     ─
+   ╰────
+
+# duplicated_capturing_group_names
+
+  × Invalid regular expression: Duplicated capturing group names
+   ╭─[/(?<n>.)(?<n>.)/:1:5]
+ 1 │ /(?<n>.)(?<n>.)/
+   ·     ─      ─
+   ╰────
+
+# empty_group_specifier
+
+  × Invalid regular expression: Unterminated capturing group name
+   ╭─[/(?<>a)/:1:4]
+ 1 │ /(?<>a)/
+   ·    ─
+   ╰────
+
+# lone_quantifier
+
+  × Invalid regular expression: Lone quantifier found, expected with `Atom`
+   ╭─[/+/u:1:2]
+ 1 │ /+/u
+   ·  ─
+   ╰────
+
+# invalid_braced_quantifier
+
+  × Invalid regular expression: Invalid braced quantifier
+   ╭─[/a|+/:1:4]
+ 1 │ /a|+/
+   ·    ─
+   ╰────
+
+# invalid_braced_quantifier_unicode
+
+  × Invalid regular expression: Could not parse the entire pattern
+   ╭─[/a{/u:1:3]
+ 1 │ /a{/u
+   ·   ▲
+   ╰────
+
+# too_large_number_in_braced_quantifier
+
+  × Invalid regular expression: Number is too large in decimal digits
+   ╭─[/x{99999999999999999999999999999999999999999999999999}/:1:4]
+ 1 │ /x{99999999999999999999999999999999999999999999999999}/
+   ·    ───────────────────
+   ╰────
+
+# braced_quantifier_out_of_order
+
+  × Invalid regular expression: Numbers out of order in braced quantifier
+   ╭─[/a{2,1}/:1:3]
+ 1 │ /a{2,1}/
+   ·   ─────
+   ╰────
+
+# unterminated_group
+
+  × Invalid regular expression: Unterminated capturing group
+   ╭─[/(/:1:2]
+ 1 │ /(/
+   ·  ─
+   ╰────
+
+# unterminated_character_class
+
+  × Invalid regular expression: Unterminated character class
+   ╭─[/[/:1:2]
+ 1 │ /[/
+   ·  ─
+   ╰────
+
+# invalid_indexed_reference
+
+  × Invalid regular expression: Invalid indexed reference
+   ╭─[/\1/u:1:2]
+ 1 │ /\1/u
+   ·  ──
+   ╰────
+
+# invalid_named_reference
+
+  × Invalid regular expression: Group specifier is empty
+   ╭─[/\k<a>/u:1:2]
+ 1 │ /\k<a>/u
+   ·  ─────
+   ╰────
+
+# invalid_unicode_property_name_negative_strings
+
+  × Invalid regular expression: Invalid property name `Basic_Emoji`(negative + property of strings)
+   ╭─[/\P{Basic_Emoji}/v:1:2]
+ 1 │ /\P{Basic_Emoji}/v
+   ·  ───────────────
+   ╰────
+
+# invalid_unicode_property_of_strings
+
+  × Invalid regular expression: Invalid unicode property `Basic_Emoji`
+   ╭─[/\p{Basic_Emoji}/u:1:5]
+ 1 │ /\p{Basic_Emoji}/u
+   ·     ───────────
+   ╰────
+  help: Enable `UnicodeSetsMode` to use this property
+
+# invalid_unicode_property
+
+  × Invalid regular expression: Invalid unicode property name and/or value
+   ╭─[/\p{Foo}/u:1:5]
+ 1 │ /\p{Foo}/u
+   ·     ───
+   ╰────
+
+# character_class_range_out_of_order
+
+  × Invalid regular expression: Character class atom range out of order
+   ╭─[/[z-a]/:1:4]
+ 1 │ /[z-a]/
+   ·    ──
+   ╰────
+
+# character_class_range_invalid_atom
+
+  × Invalid regular expression: Character class range with invalid atom
+   ╭─[/[\d-z]/u:1:3]
+ 1 │ /[\d-z]/u
+   ·   ────
+   ╰────
+
+# invalid_class_atom
+
+  × Invalid regular expression: Character class range with invalid atom
+   ╭─[/[a-\d]/u:1:3]
+ 1 │ /[a-\d]/u
+   ·   ────
+   ╰────
+
+# empty_class_set_expression
+
+  × Invalid regular expression: Expected nonempty class set expression
+   ╭─[/[&&]/v:1:3]
+ 1 │ /[&&]/v
+   ·   ▲
+   ╰────
+
+# class_intersection_unexpected_ampersand
+
+  × Invalid regular expression: Unexpected `&` inside of class intersection
+   ╭─[/[a&&&b]/v:1:6]
+ 1 │ /[a&&&b]/v
+   ·      ─
+   ╰────
+
+# class_set_expression_invalid_character
+
+  × Invalid regular expression: Unexpected character inside of class intersection
+   ╭─[/[a&&]/v:1:6]
+ 1 │ /[a&&]/v
+   ·      ▲
+   ╰────
+
+# class_set_expression_invalid_character
+
+  × Invalid regular expression: Unexpected character inside of class intersection
+   ╭─[/[a&&b(]/v:1:7]
+ 1 │ /[a&&b(]/v
+   ·       ▲
+   ╰────
+
+# character_class_contents_invalid_operands
+
+  × Invalid regular expression: Invalid class operands inside of character class contents
+   ╭─[/[[^\q{ng}]]/v:1:3]
+ 1 │ /[[^\q{ng}]]/v
+   ·   ─────────
+   ╰────
+
+# too_large_number_digits
+
+  × Invalid regular expression: Number is too large in hex digits
+   ╭─[/\u{FFFFFFFFFFFFFFFFFFFFFFFFFFFFFFF}/u:1:5]
+ 1 │ /\u{FFFFFFFFFFFFFFFFFFFFFFFFFFFFFFF}/u
+   ·     ────────
+   ╰────
+
+# invalid_unicode_escape_sequence
+
+  × Invalid regular expression: Invalid unicode escape sequence
+   ╭─[/\ua/u:1:3]
+ 1 │ /\ua/u
+   ·   ─
+   ╰────
+
+# invalid_surrogate_pair
+
+  × Invalid regular expression: Invalid unicode escape sequence
+   ╭─[/\u{110000}/u:1:3]
+ 1 │ /\u{110000}/u
+   ·   ─
+   ╰────
+
+# invalid_extended_atom_escape
+
+  × Invalid regular expression: Could not parse the entire pattern
+   ╭─[/\c0/u:1:3]
+ 1 │ /\c0/u
+   ·   ▲
+   ╰────
+
+# invalid_modifiers
+
+  × Invalid regular expression: Invalid modifiers
+   ╭─[/(?ii:.)/:1:4]
+ 1 │ /(?ii:.)/
+   ·    ──
+   ╰────
+
+# unknown_modifiers
+
+  × Invalid regular expression: Unknown modifiers
+   ╭─[/(?a:.)/:1:4]
+ 1 │ /(?a:.)/
+   ·    ▲
+   ╰────
+
+# parse_pattern_incomplete
+
+  × Invalid regular expression: Could not parse the entire pattern
+   ╭─[/)/v:1:2]
+ 1 │ /)/v
+   ·  ▲
+   ╰────