diff --git a/doc/manual/rl-next/remove-xp-parse-toml-timestamps.md b/doc/manual/rl-next/remove-xp-parse-toml-timestamps.md
new file mode 100644
index 000000000..471f40988
--- /dev/null
+++ b/doc/manual/rl-next/remove-xp-parse-toml-timestamps.md
@@ -0,0 +1,17 @@
+---
+synopsis: Remove the `parse-toml-timestamps` experimental feature
+category: "Breaking Changes"
+credits: [emilazy]
+---
+
+The `parse-toml-timestamps` experimental feature has been removed.
+
+This feature used in‐band signalling to mark timestamps, making it
+impossible to unambiguously parse TOML documents. It also exposed
+implementation‐defined behaviour in the TOML specification that
+changed in the toml11 parser library.
+
+Any interface for parsing TOML timestamps suitable for future
+stabilization would necessarily involve breaking changes, and there
+is no evidence this experimental feature is being relied upon in the
+wild, so it has been removed.
diff --git a/lix/libexpr/primops/fromTOML.cc b/lix/libexpr/primops/fromTOML.cc
index a66ccfb4e..9d4b5e6ab 100644
--- a/lix/libexpr/primops/fromTOML.cc
+++ b/lix/libexpr/primops/fromTOML.cc
@@ -6,80 +6,6 @@
 
 namespace nix {
 
-/**
- * This is what toml11 < 4.0 did when choosing the subsecond precision.
- * TOML 1.0.0 spec doesn't define how sub-millisecond ranges should be handled and calls it
- * implementation defined behavior. For a lack of a better choice we stick with what older versions
- * of toml11 did [1].
- *
- * [1]:
- * https://github.com/ToruNiina/toml11/blob/dcfe39a783a94e8d52c885e5883a6fbb21529019/toml/datetime.hpp#L282
- */
-static size_t normalizeSubsecondPrecision(toml::local_time lt)
-{
-    auto millis = lt.millisecond;
-    auto micros = lt.microsecond;
-    auto nanos = lt.nanosecond;
-    if (millis != 0 || micros != 0 || nanos != 0) {
-        if (micros != 0 || nanos != 0) {
-            if (nanos != 0) {
-                return 9;
-            }
-            return 6;
-        }
-        return 3;
-    }
-    return 0;
-}
-
-/**
- * Normalize date/time formats to serialize to the same strings as versions prior to toml11 4.0.
- *
- * Several things to consider:
- *
- * 1. Sub-millisecond range is represented the same way as in toml11 versions prior to 4.0.
- * Precision is rounded towards the next multiple of 3 or capped at 9 digits.
- * 2. Seconds must be specified. This may become optional in (yet unreleased) TOML 1.1.0, but 1.0.0
- * defined local time in terms of RFC3339 [1].
- * 3. date-time separator (`t`, `T` or space ` `) is canonicalized to an upper T. This is compliant
- * with RFC3339 [1] 5.6: > Applications that generate this format SHOULD use upper case letters.
- *
- * [1]: https://datatracker.ietf.org/doc/html/rfc3339#section-5.6
- */
-static void normalizeDatetimeFormat(toml::value & t)
-{
-    if (t.is_local_datetime()) {
-        auto & ldt = t.as_local_datetime();
-        t.as_local_datetime_fmt() = {
-            .delimiter = toml::datetime_delimiter_kind::upper_T,
-            // https://datatracker.ietf.org/doc/html/rfc3339#section-5.6
-            .has_seconds = true, // Mandated by TOML 1.0.0
-            .subsecond_precision = normalizeSubsecondPrecision(ldt.time),
-        };
-        return;
-    }
-
-    if (t.is_offset_datetime()) {
-        auto & odt = t.as_offset_datetime();
-        t.as_offset_datetime_fmt() = {
-            .delimiter = toml::datetime_delimiter_kind::upper_T,
-            // https://datatracker.ietf.org/doc/html/rfc3339#section-5.6
-            .has_seconds = true, // Mandated by TOML 1.0.0
-            .subsecond_precision = normalizeSubsecondPrecision(odt.time),
-        };
-        return;
-    }
-
-    if (t.is_local_time()) {
-        auto & lt = t.as_local_time();
-        t.as_local_time_fmt() = {
-            .has_seconds = true, // Mandated by TOML 1.0.0
-            .subsecond_precision = normalizeSubsecondPrecision(lt),
-        };
-        return;
-    }
-}
-
 void prim_fromTOML(EvalState & state, Value ** args, Value & val)
 {
     auto toml = state.forceStringNoCtx(
@@ -124,20 +50,10 @@ void prim_fromTOML(EvalState & state, Value ** args, Value & val)
         case toml::value_t::local_datetime:
         case toml::value_t::offset_datetime:
         case toml::value_t::local_date:
-        case toml::value_t::local_time: {
-            if (experimentalFeatureSettings.isEnabled(Xp::ParseTomlTimestamps)) {
-                normalizeDatetimeFormat(t);
-                auto attrs = state.ctx.buildBindings(2);
-                attrs.alloc("_type").mkString("timestamp");
-                std::ostringstream s;
-                s << t;
-                attrs.alloc("value").mkString(s.str());
-                v.mkAttrs(attrs);
-            } else {
-                // NOLINTNEXTLINE(lix-foreign-exceptions)
-                throw std::runtime_error("Dates and times are not supported");
-            }
-        } break;
+        case toml::value_t::local_time:
+            // NOLINTNEXTLINE(lix-foreign-exceptions)
+            throw std::runtime_error("Dates and times are not supported");
+            break;
         case toml::value_t::empty:
             v.mkNull();
             break;
diff --git a/lix/libutil/experimental-features/parse-toml-timestamps.md b/lix/libutil/experimental-features/parse-toml-timestamps.md
deleted file mode 100644
index 9dbfb70d0..000000000
--- a/lix/libutil/experimental-features/parse-toml-timestamps.md
+++ /dev/null
@@ -1,5 +0,0 @@
----
-name: parse-toml-timestamps
-internalName: ParseTomlTimestamps
----
-Allow parsing of timestamps in builtins.fromTOML.
diff --git a/lix/libutil/meson.build b/lix/libutil/meson.build
index 9ae86de05..71d55154c 100644
--- a/lix/libutil/meson.build
+++ b/lix/libutil/meson.build
@@ -158,7 +158,6 @@ experimental_feature_definitions = files(
   'experimental-features/lix-custom-sub-commands.md',
   'experimental-features/nix-command.md',
   'experimental-features/no-url-literals.md',
-  'experimental-features/parse-toml-timestamps.md',
   'experimental-features/pipe-operator.md',
   'experimental-features/read-only-local-store.md',
   'experimental-features/repl-automation.md',
diff --git a/tests/functional/lang/eval-okay-fromTOML-timestamps.exp b/tests/functional/lang/eval-okay-fromTOML-timestamps.exp
deleted file mode 100644
index 56e610533..000000000
--- a/tests/functional/lang/eval-okay-fromTOML-timestamps.exp
+++ /dev/null
@@ -1 +0,0 @@
-{ "1234" = "value"; "127.0.0.1" = "value"; a = { b = { c = { }; }; }; arr1 = [ 1 2 3 ]; arr2 = [ "red" "yellow" "green" ]; arr3 = [ [ 1 2 ] [ 3 4 5 ] ]; arr4 = [ "all" "strings" "are the same" "type" ]; arr5 = [ [ 1 2 ] [ "a" "b" "c" ] ]; arr7 = [ 1 2 3 ]; arr8 = [ 1 2 ]; bare-key = "value"; bare_key = "value"; bin1 = 214; bool1 = true; bool2 = false; "character encoding" = "value"; d = { e = { f = { }; }; }; dog = { "tater.man" = { type = { name = "pug"; }; }; }; flt1 = 1; flt2 = 3.1415; flt3 = -0.01; flt4 = 5e+22; flt5 = 1e+06; flt6 = -0.02; flt7 = 6.626e-34; flt8 = 9.22462e+06; fruit = [ { name = "apple"; physical = { color = "red"; shape = "round"; }; variety = [ { name = "red delicious"; } { name = "granny smith"; } ]; } { name = "banana"; variety = [ { name = "plantain"; } ]; } ]; g = { h = { i = { }; }; }; hex1 = 3735928559; hex2 = 3735928559; hex3 = 3735928559; int1 = 99; int2 = 42; int3 = 0; int4 = -17; int5 = 1000; int6 = 5349221; int7 = 12345; j = { "ʞ" = { l = { }; }; }; key = "value"; key2 = "value"; ld1 = { _type = "timestamp"; value = "1979-05-27"; }; ldt1 = { _type = "timestamp"; value = "1979-05-27T07:32:00"; }; ldt10 = { _type = "timestamp"; value = "1979-05-27T00:32:00.123456789"; }; ldt11 = { _type = "timestamp"; value = "1979-05-27T00:32:00.123456789"; }; ldt2 = { _type = "timestamp"; value = "1979-05-27T07:32:00.100"; }; ldt3 = { _type = "timestamp"; value = "1979-05-27T07:32:00.120"; }; ldt4 = { _type = "timestamp"; value = "1979-05-27T07:32:00.123"; }; ldt5 = { _type = "timestamp"; value = "1979-05-27T00:32:00.123400"; }; ldt6 = { _type = "timestamp"; value = "1979-05-27T00:32:00.123450"; }; ldt7 = { _type = "timestamp"; value = "1979-05-27T00:32:00.123456"; }; ldt8 = { _type = "timestamp"; value = "1979-05-27T00:32:00.123456700"; }; ldt9 = { _type = "timestamp"; value = "1979-05-27T00:32:00.123456780"; }; lt1 = { _type = "timestamp"; value = "07:32:00"; }; lt10 = { _type = "timestamp"; value = "00:32:00.123456789"; }; lt11 = { _type = "timestamp"; value = "00:32:00.123456789"; }; lt2 = { _type = "timestamp"; value = "00:32:00.100"; }; lt3 = { _type = "timestamp"; value = "00:32:00.120"; }; lt4 = { _type = "timestamp"; value = "00:32:00.123"; }; lt5 = { _type = "timestamp"; value = "00:32:00.123400"; }; lt6 = { _type = "timestamp"; value = "00:32:00.123450"; }; lt7 = { _type = "timestamp"; value = "00:32:00.123456"; }; lt8 = { _type = "timestamp"; value = "00:32:00.123456700"; }; lt9 = { _type = "timestamp"; value = "00:32:00.123456780"; }; name = "Orange"; oct1 = 342391; oct2 = 493; odt1 = { _type = "timestamp"; value = "1979-05-27T07:32:00Z"; }; odt10 = { _type = "timestamp"; value = "1979-05-27T07:32:00.123456Z"; }; odt11 = { _type = "timestamp"; value = "1979-05-27T07:32:00.123456700Z"; }; odt12 = { _type = "timestamp"; value = "1979-05-27T07:32:00.123456780Z"; }; odt13 = { _type = "timestamp"; value = "1979-05-27T07:32:00.123456789Z"; }; odt14 = { _type = "timestamp"; value = "1979-05-27T07:32:00.123456789Z"; }; odt2 = { _type = "timestamp"; value = "1979-05-27T00:32:00-07:00"; }; odt3 = { _type = "timestamp"; value = "1979-05-27T00:32:00.999999-07:00"; }; odt4 = { _type = "timestamp"; value = "1979-05-27T07:32:00Z"; }; odt5 = { _type = "timestamp"; value = "1979-05-27T07:32:00.100Z"; }; odt6 = { _type = "timestamp"; value = "1979-05-27T07:32:00.120Z"; }; odt7 = { _type = "timestamp"; value = "1979-05-27T07:32:00.123Z"; }; odt8 = { _type = "timestamp"; value = "1979-05-27T07:32:00.123400Z"; }; odt9 = { _type = "timestamp"; value = "1979-05-27T07:32:00.123450Z"; }; physical = { color = "orange"; shape = "round"; }; products = [ { name = "Hammer"; sku = 738594937; } { } { color = "gray"; name = "Nail"; sku = 284758393; } ]; "quoted \"value\"" = "value"; site = { "google.com" = true; }; str = "I'm a string. \"You can quote me\". Name\tJosé\nLocation\tSF."; table-1 = { key1 = "some string"; key2 = 123; }; table-2 = { key1 = "another string"; key2 = 456; }; x = { y = { z = { w = { animal = { type = { name = "pug"; }; }; name = { first = "Tom"; last = "Preston-Werner"; }; point = { x = 1; y = 2; }; }; }; }; }; "ʎǝʞ" = "value"; }
diff --git a/tests/functional/lang/eval-okay-fromTOML-timestamps.flags b/tests/functional/lang/eval-okay-fromTOML-timestamps.flags
deleted file mode 100644
index 9ed39dc6b..000000000
--- a/tests/functional/lang/eval-okay-fromTOML-timestamps.flags
+++ /dev/null
@@ -1 +0,0 @@
---extra-experimental-features parse-toml-timestamps
diff --git a/tests/functional/lang/eval-okay-fromTOML-timestamps.nix b/tests/functional/lang/eval-okay-fromTOML-timestamps.nix
deleted file mode 100644
index d8f3a03e9..000000000
--- a/tests/functional/lang/eval-okay-fromTOML-timestamps.nix
+++ /dev/null
@@ -1,172 +0,0 @@
-builtins.fromTOML ''
-  key = "value"
-  bare_key = "value"
-  bare-key = "value"
-  1234 = "value"
-
-  "127.0.0.1" = "value"
-  "character encoding" = "value"
-  "ʎǝʞ" = "value"
-  'key2' = "value"
-  'quoted "value"' = "value"
-
-  name = "Orange"
-
-  physical.color = "orange"
-  physical.shape = "round"
-  site."google.com" = true
-
-  # This is legal according to the spec, but cpptoml doesn't handle it.
-  #a.b.c = 1
-  #a.d = 2
-
-  str = "I'm a string. \"You can quote me\". Name\tJos\u00E9\nLocation\tSF."
-
-  int1 = +99
-  int2 = 42
-  int3 = 0
-  int4 = -17
-  int5 = 1_000
-  int6 = 5_349_221
-  int7 = 1_2_3_4_5
-
-  hex1 = 0xDEADBEEF
-  hex2 = 0xdeadbeef
-  hex3 = 0xdead_beef
-
-  oct1 = 0o01234567
-  oct2 = 0o755
-
-  bin1 = 0b11010110
-
-  flt1 = +1.0
-  flt2 = 3.1415
-  flt3 = -0.01
-  flt4 = 5e+22
-  flt5 = 1e6
-  flt6 = -2E-2
-  flt7 = 6.626e-34
-  flt8 = 9_224_617.445_991_228_313
-
-  bool1 = true
-  bool2 = false
-
-  odt1 = 1979-05-27T07:32:00Z
-  odt2 = 1979-05-27T00:32:00-07:00
-  odt3 = 1979-05-27T00:32:00.999999-07:00
-  odt4 = 1979-05-27 07:32:00Z
-  # milliseconds
-  odt5 = 1979-05-27 07:32:00.1Z
-  odt6 = 1979-05-27 07:32:00.12Z
-  odt7 = 1979-05-27 07:32:00.123Z
-  # microseconds
-  odt8 = 1979-05-27t07:32:00.1234Z
-  odt9 = 1979-05-27t07:32:00.12345Z
-  odt10 = 1979-05-27t07:32:00.123456Z
-  # nanoseconds
-  odt11 = 1979-05-27 07:32:00.1234567Z
-  odt12 = 1979-05-27 07:32:00.12345678Z
-  odt13 = 1979-05-27 07:32:00.123456789Z
-  # no more precision after nanoseconds
-  odt14 = 1979-05-27t07:32:00.1234567891Z
-
-  ldt1 = 1979-05-27T07:32:00
-  # milliseconds
-  ldt2 = 1979-05-27T07:32:00.1
-  ldt3 = 1979-05-27T07:32:00.12
-  ldt4 = 1979-05-27T07:32:00.123
-  # microseconds
-  ldt5 = 1979-05-27t00:32:00.1234
-  ldt6 = 1979-05-27t00:32:00.12345
-  ldt7 = 1979-05-27t00:32:00.123456
-  # nanoseconds
-  ldt8 = 1979-05-27 00:32:00.1234567
-  ldt9 = 1979-05-27 00:32:00.12345678
-  ldt10 = 1979-05-27 00:32:00.123456789
-  # no more precision after nanoseconds
-  ldt11 = 1979-05-27t00:32:00.1234567891
-
-  ld1 = 1979-05-27
-  lt1 = 07:32:00
-  # milliseconds
-  lt2 = 00:32:00.1
-  lt3 = 00:32:00.12
-  lt4 = 00:32:00.123
-  # microseconds
-  lt5 = 00:32:00.1234
-  lt6 = 00:32:00.12345
-  lt7 = 00:32:00.123456
-  # nanoseconds
-  lt8 = 00:32:00.1234567
-  lt9 = 00:32:00.12345678
-  lt10 = 00:32:00.123456789
-  # no more precision after nanoseconds
-  lt11 = 00:32:00.1234567891
-
-  arr1 = [ 1, 2, 3 ]
-  arr2 = [ "red", "yellow", "green" ]
-  arr3 = [ [ 1, 2 ], [3, 4, 5] ]
-  arr4 = [ "all", 'strings', """are the same""", ''''type'''']
-  arr5 = [ [ 1, 2 ], ["a", "b", "c"] ]
-
-  arr7 = [
-    1, 2, 3
-  ]
-
-  arr8 = [
-    1,
-    2, # this is ok
-  ]
-
-  [table-1]
-  key1 = "some string"
-  key2 = 123
-
-
-  [table-2]
-  key1 = "another string"
-  key2 = 456
-
-  [dog."tater.man"]
-  type.name = "pug"
-
-  [a.b.c]
-  [ d.e.f ]
-  [ g .  h  . i ]
-  [ j . "ʞ" . 'l' ]
-  [x.y.z.w]
-
-  name = { first = "Tom", last = "Preston-Werner" }
-  point = { x = 1, y = 2 }
-  animal = { type.name = "pug" }
-
-  [[products]]
-  name = "Hammer"
-  sku = 738594937
-
-  [[products]]
-
-  [[products]]
-  name = "Nail"
-  sku = 284758393
-  color = "gray"
-
-  [[fruit]]
-    name = "apple"
-
-    [fruit.physical]
-      color = "red"
-      shape = "round"
-
-    [[fruit.variety]]
-      name = "red delicious"
-
-    [[fruit.variety]]
-      name = "granny smith"
-
-  [[fruit]]
-    name = "banana"
-
-    [[fruit.variety]]
-      name = "plantain"
-''