diff --git a/src/core/include/mp-units/quantity.h b/src/core/include/mp-units/quantity.h
index c85bc0bec..ba362b483 100644
--- a/src/core/include/mp-units/quantity.h
+++ b/src/core/include/mp-units/quantity.h
@@ -151,10 +151,18 @@ class quantity {
   quantity& operator=(quantity&&) = default;
 
   // data access
+#ifdef __cpp_explicit_this_parameter
+  template<typename Self>
+  [[nodiscard]] constexpr auto&& number(this Self&& self) noexcept
+  {
+    return std::forward<Self>(self).number_;
+  }
+#else
   [[nodiscard]] constexpr rep& number() & noexcept { return number_; }
   [[nodiscard]] constexpr const rep& number() const& noexcept { return number_; }
   [[nodiscard]] constexpr rep&& number() && noexcept { return std::move(number_); }
   [[nodiscard]] constexpr const rep&& number() const&& noexcept { return std::move(number_); }
+#endif
 
   template<Unit U>
     requires requires(quantity q) { q[U{}]; }
diff --git a/src/core/include/mp-units/quantity_point.h b/src/core/include/mp-units/quantity_point.h
index 848f7779f..9b185b93a 100644
--- a/src/core/include/mp-units/quantity_point.h
+++ b/src/core/include/mp-units/quantity_point.h
@@ -140,10 +140,18 @@ class quantity_point {
   quantity_point& operator=(quantity_point&&) = default;
 
   // data access
+#ifdef __cpp_explicit_this_parameter
+  template<typename Self>
+  [[nodiscard]] constexpr auto&& relative(this Self&& self) noexcept
+  {
+    return std::forward<Self>(self).q_;
+  }
+#else
   [[nodiscard]] constexpr quantity_type& relative() & noexcept { return q_; }
   [[nodiscard]] constexpr const quantity_type& relative() const& noexcept { return q_; }
   [[nodiscard]] constexpr quantity_type&& relative() && noexcept { return std::move(q_); }
   [[nodiscard]] constexpr const quantity_type&& relative() const&& noexcept { return std::move(q_); }
+#endif
 
   [[nodiscard]] constexpr Quantity auto absolute() const noexcept
   {