diff --git a/Cargo.toml b/Cargo.toml
index 2830bd4302..9dab1297e3 100644
--- a/Cargo.toml
+++ b/Cargo.toml
@@ -17,6 +17,7 @@ rust-version = "1.57.0"
 name = "chrono"
 
 [features]
+# Don't forget to adjust `ALL_NON_EXCLUSIVE_FEATURES` in CI scripts when adding a feature or an optional dependency.
 default = ["clock", "std", "wasmbind"]
 alloc = []
 libc = []
@@ -25,12 +26,20 @@ std = ["alloc"]
 clock = ["std", "winapi", "iana-time-zone", "android-tzdata"]
 wasmbind = ["wasm-bindgen", "js-sys"]
 unstable-locales = ["pure-rust-locales"]
+rkyv = ["rkyv-32"]
+# Note that rkyv-16, rkyv-32, and rkyv-64 are mutually exclusive.
+rkyv-16 = ["dep:rkyv", "rkyv?/size_16"]
+rkyv-32 = ["dep:rkyv", "rkyv?/size_32"]
+rkyv-64 = ["dep:rkyv", "rkyv?/size_64"]
+rkyv-validation = ["rkyv?/validation"]
+# Features for internal use only:
 __internal_bench = []
+__internal_rkyv = ["dep:rkyv"]
 
 [dependencies]
 serde = { version = "1.0.99", default-features = false, optional = true }
 pure-rust-locales = { version = "0.7", optional = true }
-rkyv = { version = "0.7", optional = true }
+rkyv = { version = "0.7", optional = true, default-features = false }
 arbitrary = { version = "1.0.0", features = ["derive"], optional = true }
 
 [target.'cfg(all(target_arch = "wasm32", not(any(target_os = "emscripten", target_os = "wasi"))))'.dependencies]
diff --git a/src/datetime/mod.rs b/src/datetime/mod.rs
index 6efd15ef8c..b0520eb549 100644
--- a/src/datetime/mod.rs
+++ b/src/datetime/mod.rs
@@ -28,7 +28,7 @@ use crate::offset::Local;
 use crate::offset::{FixedOffset, Offset, TimeZone, Utc};
 use crate::{Datelike, Months, TimeDelta, Timelike, Weekday};
 
-#[cfg(feature = "rkyv")]
+#[cfg(feature = "__internal_rkyv")]
 use rkyv::{Archive, Deserialize, Serialize};
 
 /// documented at re-export site
@@ -73,7 +73,10 @@ pub enum SecondsFormat {
 /// the general-purpose constructors are all via the methods on the
 /// [`TimeZone`](./offset/trait.TimeZone.html) implementations.
 #[derive(Clone)]
-#[cfg_attr(feature = "rkyv", derive(Archive, Deserialize, Serialize))]
+#[cfg_attr(
+    any(feature = "rkyv_16", feature = "rkyv_32", feature = "rkyv_64"),
+    derive(Archive, Deserialize, Serialize)
+)]
 pub struct DateTime<Tz: TimeZone> {
     datetime: NaiveDateTime,
     offset: Tz::Offset,
diff --git a/src/lib.rs b/src/lib.rs
index 0d092fcec1..dd319b4ff9 100644
--- a/src/lib.rs
+++ b/src/lib.rs
@@ -544,7 +544,7 @@ pub mod serde {
 /// Zero-copy serialization/deserialization with rkyv.
 ///
 /// This module re-exports the `Archived*` versions of chrono's types.
-#[cfg(feature = "rkyv")]
+#[cfg(feature = "__internal_rkyv")]
 pub mod rkyv {
     pub use crate::datetime::ArchivedDateTime;
     pub use crate::month::ArchivedMonth;
diff --git a/src/month.rs b/src/month.rs
index acb96a2da1..7c09f91aa4 100644
--- a/src/month.rs
+++ b/src/month.rs
@@ -1,6 +1,6 @@
 use core::fmt;
 
-#[cfg(feature = "rkyv")]
+#[cfg(feature = "__internal_rkyv")]
 use rkyv::{Archive, Deserialize, Serialize};
 
 use crate::OutOfRange;
@@ -29,9 +29,12 @@ use crate::OutOfRange;
 /// Can be Serialized/Deserialized with serde
 // Actual implementation is zero-indexed, API intended as 1-indexed for more intuitive behavior.
 #[derive(PartialEq, Eq, Copy, Clone, Debug, Hash, PartialOrd, Ord)]
-#[cfg_attr(feature = "rkyv", derive(Archive, Deserialize, Serialize))]
 #[cfg_attr(
-    feature = "rkyv",
+    any(feature = "rkyv_16", feature = "rkyv_32", feature = "rkyv_64"),
+    derive(Archive, Deserialize, Serialize)
+)]
+#[cfg_attr(
+    any(feature = "rkyv_16", feature = "rkyv_32", feature = "rkyv_64"),
     archive_attr(derive(Clone, Copy, PartialEq, Eq, PartialOrd, Ord, Debug, Hash))
 )]
 #[cfg_attr(feature = "arbitrary", derive(arbitrary::Arbitrary))]
diff --git a/src/naive/date.rs b/src/naive/date.rs
index faccc06024..a133c8b02f 100644
--- a/src/naive/date.rs
+++ b/src/naive/date.rs
@@ -9,7 +9,7 @@ use core::iter::FusedIterator;
 use core::ops::{Add, AddAssign, RangeInclusive, Sub, SubAssign};
 use core::{fmt, str};
 
-#[cfg(feature = "rkyv")]
+#[cfg(feature = "__internal_rkyv")]
 use rkyv::{Archive, Deserialize, Serialize};
 
 /// L10n locales.
@@ -190,9 +190,12 @@ impl Days {
 ///
 /// [proleptic Gregorian date]: crate::NaiveDate#calendar-date
 #[derive(PartialEq, Eq, Hash, PartialOrd, Ord, Copy, Clone)]
-#[cfg_attr(feature = "rkyv", derive(Archive, Deserialize, Serialize))]
 #[cfg_attr(
-    feature = "rkyv",
+    any(feature = "rkyv_16", feature = "rkyv_32", feature = "rkyv_64"),
+    derive(Archive, Deserialize, Serialize)
+)]
+#[cfg_attr(
+    any(feature = "rkyv_16", feature = "rkyv_32", feature = "rkyv_64"),
     archive_attr(derive(Clone, Copy, PartialEq, Eq, PartialOrd, Ord, Debug, Hash))
 )]
 pub struct NaiveDate {
diff --git a/src/naive/datetime/mod.rs b/src/naive/datetime/mod.rs
index 3816be9c42..ae00f70b57 100644
--- a/src/naive/datetime/mod.rs
+++ b/src/naive/datetime/mod.rs
@@ -10,7 +10,7 @@ use core::ops::{Add, AddAssign, Sub, SubAssign};
 use core::time::Duration;
 use core::{fmt, str};
 
-#[cfg(feature = "rkyv")]
+#[cfg(feature = "__internal_rkyv")]
 use rkyv::{Archive, Deserialize, Serialize};
 
 #[cfg(feature = "alloc")]
@@ -72,9 +72,12 @@ pub const MAX_DATETIME: NaiveDateTime = NaiveDateTime::MAX;
 /// assert_eq!(dt.num_seconds_from_midnight(), 33011);
 /// ```
 #[derive(PartialEq, Eq, Hash, PartialOrd, Ord, Copy, Clone)]
-#[cfg_attr(feature = "rkyv", derive(Archive, Deserialize, Serialize))]
 #[cfg_attr(
-    feature = "rkyv",
+    any(feature = "rkyv_16", feature = "rkyv_32", feature = "rkyv_64"),
+    derive(Archive, Deserialize, Serialize)
+)]
+#[cfg_attr(
+    any(feature = "rkyv_16", feature = "rkyv_32", feature = "rkyv_64"),
     archive_attr(derive(Clone, Copy, PartialEq, Eq, PartialOrd, Ord, Debug, Hash))
 )]
 #[cfg_attr(feature = "arbitrary", derive(arbitrary::Arbitrary))]
diff --git a/src/naive/isoweek.rs b/src/naive/isoweek.rs
index 606699659b..3fdf9a9793 100644
--- a/src/naive/isoweek.rs
+++ b/src/naive/isoweek.rs
@@ -7,7 +7,7 @@ use core::fmt;
 
 use super::internals::{DateImpl, Of, YearFlags};
 
-#[cfg(feature = "rkyv")]
+#[cfg(feature = "__internal_rkyv")]
 use rkyv::{Archive, Deserialize, Serialize};
 
 /// ISO 8601 week.
@@ -17,9 +17,12 @@ use rkyv::{Archive, Deserialize, Serialize};
 /// One can retrieve this type from the existing [`Datelike`](../trait.Datelike.html) types
 /// via the [`Datelike::iso_week`](../trait.Datelike.html#tymethod.iso_week) method.
 #[derive(PartialEq, Eq, PartialOrd, Ord, Copy, Clone, Hash)]
-#[cfg_attr(feature = "rkyv", derive(Archive, Deserialize, Serialize))]
 #[cfg_attr(
-    feature = "rkyv",
+    any(feature = "rkyv_16", feature = "rkyv_32", feature = "rkyv_64"),
+    derive(Archive, Deserialize, Serialize)
+)]
+#[cfg_attr(
+    any(feature = "rkyv_16", feature = "rkyv_32", feature = "rkyv_64"),
     archive_attr(derive(Clone, Copy, PartialEq, Eq, PartialOrd, Ord, Debug, Hash))
 )]
 pub struct IsoWeek {
diff --git a/src/naive/time/mod.rs b/src/naive/time/mod.rs
index f2a0693ffd..76682ce608 100644
--- a/src/naive/time/mod.rs
+++ b/src/naive/time/mod.rs
@@ -9,7 +9,7 @@ use core::ops::{Add, AddAssign, Sub, SubAssign};
 use core::time::Duration;
 use core::{fmt, str};
 
-#[cfg(feature = "rkyv")]
+#[cfg(feature = "__internal_rkyv")]
 use rkyv::{Archive, Deserialize, Serialize};
 
 #[cfg(feature = "alloc")]
@@ -199,9 +199,12 @@ mod tests;
 /// Since Chrono alone cannot determine any existence of leap seconds,
 /// **there is absolutely no guarantee that the leap second read has actually happened**.
 #[derive(PartialEq, Eq, Hash, PartialOrd, Ord, Copy, Clone)]
-#[cfg_attr(feature = "rkyv", derive(Archive, Deserialize, Serialize))]
 #[cfg_attr(
-    feature = "rkyv",
+    any(feature = "rkyv_16", feature = "rkyv_32", feature = "rkyv_64"),
+    derive(Archive, Deserialize, Serialize)
+)]
+#[cfg_attr(
+    any(feature = "rkyv_16", feature = "rkyv_32", feature = "rkyv_64"),
     archive_attr(derive(Clone, Copy, PartialEq, Eq, PartialOrd, Ord, Debug, Hash))
 )]
 pub struct NaiveTime {
diff --git a/src/offset/fixed.rs b/src/offset/fixed.rs
index 1c3dc5e366..4c5477c54a 100644
--- a/src/offset/fixed.rs
+++ b/src/offset/fixed.rs
@@ -6,7 +6,7 @@
 use core::fmt;
 use core::str::FromStr;
 
-#[cfg(feature = "rkyv")]
+#[cfg(feature = "__internal_rkyv")]
 use rkyv::{Archive, Deserialize, Serialize};
 
 use super::{LocalResult, Offset, TimeZone};
@@ -20,8 +20,14 @@ use crate::{NaiveDateTime, ParseError};
 /// `DateTime<FixedOffset>` instances. See the [`east_opt`](#method.east_opt) and
 /// [`west_opt`](#method.west_opt) methods for examples.
 #[derive(PartialEq, Eq, Hash, Copy, Clone)]
-#[cfg_attr(feature = "rkyv", derive(Archive, Deserialize, Serialize))]
-#[cfg_attr(feature = "rkyv", archive_attr(derive(Clone, Copy, PartialEq, Eq, Hash, Debug)))]
+#[cfg_attr(
+    any(feature = "rkyv_16", feature = "rkyv_32", feature = "rkyv_64"),
+    derive(Archive, Deserialize, Serialize)
+)]
+#[cfg_attr(
+    any(feature = "rkyv_16", feature = "rkyv_32", feature = "rkyv_64"),
+    archive_attr(derive(Clone, Copy, PartialEq, Eq, Hash, Debug))
+)]
 pub struct FixedOffset {
     local_minus_utc: i32,
 }
diff --git a/src/offset/local/mod.rs b/src/offset/local/mod.rs
index bc48b322e2..30816d1965 100644
--- a/src/offset/local/mod.rs
+++ b/src/offset/local/mod.rs
@@ -3,7 +3,7 @@
 
 //! The local (system) time zone.
 
-#[cfg(feature = "rkyv")]
+#[cfg(feature = "__internal_rkyv")]
 use rkyv::{Archive, Deserialize, Serialize};
 
 use super::fixed::FixedOffset;
@@ -101,8 +101,14 @@ mod tz_info;
 /// assert!(dt1 >= dt2);
 /// ```
 #[derive(Copy, Clone, Debug)]
-#[cfg_attr(feature = "rkyv", derive(Archive, Deserialize, Serialize))]
-#[cfg_attr(feature = "rkyv", archive_attr(derive(Clone, Copy, Debug)))]
+#[cfg_attr(
+    any(feature = "rkyv_16", feature = "rkyv_32", feature = "rkyv_64"),
+    derive(Archive, Deserialize, Serialize)
+)]
+#[cfg_attr(
+    any(feature = "rkyv_16", feature = "rkyv_32", feature = "rkyv_64"),
+    archive_attr(derive(Clone, Copy, Debug))
+)]
 #[cfg_attr(feature = "arbitrary", derive(arbitrary::Arbitrary))]
 pub struct Local;
 
diff --git a/src/offset/utc.rs b/src/offset/utc.rs
index e81949ec96..79461892eb 100644
--- a/src/offset/utc.rs
+++ b/src/offset/utc.rs
@@ -14,7 +14,7 @@ use core::fmt;
 ))]
 use std::time::{SystemTime, UNIX_EPOCH};
 
-#[cfg(feature = "rkyv")]
+#[cfg(feature = "__internal_rkyv")]
 use rkyv::{Archive, Deserialize, Serialize};
 
 use super::{FixedOffset, LocalResult, Offset, TimeZone};
@@ -40,8 +40,14 @@ use crate::DateTime;
 /// assert_eq!(Utc.with_ymd_and_hms(1970, 1, 1, 0, 1, 1).unwrap(), dt);
 /// ```
 #[derive(Copy, Clone, PartialEq, Eq, Hash)]
-#[cfg_attr(feature = "rkyv", derive(Archive, Deserialize, Serialize))]
-#[cfg_attr(feature = "rkyv", archive_attr(derive(Clone, Copy, PartialEq, Eq, Debug, Hash)))]
+#[cfg_attr(
+    any(feature = "rkyv_16", feature = "rkyv_32", feature = "rkyv_64"),
+    derive(Archive, Deserialize, Serialize)
+)]
+#[cfg_attr(
+    any(feature = "rkyv_16", feature = "rkyv_32", feature = "rkyv_64"),
+    archive_attr(derive(Clone, Copy, PartialEq, Eq, Debug, Hash))
+)]
 #[cfg_attr(feature = "arbitrary", derive(arbitrary::Arbitrary))]
 pub struct Utc;
 
diff --git a/src/time_delta.rs b/src/time_delta.rs
index 84d049275a..d3109fb864 100644
--- a/src/time_delta.rs
+++ b/src/time_delta.rs
@@ -16,7 +16,7 @@ use core::{fmt, i64};
 #[cfg(feature = "std")]
 use std::error::Error;
 
-#[cfg(feature = "rkyv")]
+#[cfg(feature = "__internal_rkyv")]
 use rkyv::{Archive, Deserialize, Serialize};
 
 /// The number of nanoseconds in a microsecond.
@@ -51,9 +51,12 @@ macro_rules! try_opt {
 ///
 /// This also allows for the negative duration; see individual methods for details.
 #[derive(Clone, Copy, PartialEq, Eq, PartialOrd, Ord, Debug, Hash)]
-#[cfg_attr(feature = "rkyv", derive(Archive, Deserialize, Serialize))]
 #[cfg_attr(
-    feature = "rkyv",
+    any(feature = "rkyv_16", feature = "rkyv_32", feature = "rkyv_64"),
+    derive(Archive, Deserialize, Serialize)
+)]
+#[cfg_attr(
+    any(feature = "rkyv_16", feature = "rkyv_32", feature = "rkyv_64"),
     archive_attr(derive(Clone, Copy, PartialEq, Eq, PartialOrd, Ord, Debug, Hash))
 )]
 pub struct TimeDelta {
diff --git a/src/weekday.rs b/src/weekday.rs
index a9c51069c4..b52395bd2f 100644
--- a/src/weekday.rs
+++ b/src/weekday.rs
@@ -1,6 +1,6 @@
 use core::fmt;
 
-#[cfg(feature = "rkyv")]
+#[cfg(feature = "__internal_rkyv")]
 use rkyv::{Archive, Deserialize, Serialize};
 
 use crate::OutOfRange;
@@ -30,8 +30,14 @@ use crate::OutOfRange;
 /// assert_eq!(sunday.pred(), Weekday::Sat);
 /// ```
 #[derive(PartialEq, Eq, Copy, Clone, Debug, Hash)]
-#[cfg_attr(feature = "rkyv", derive(Archive, Deserialize, Serialize))]
-#[cfg_attr(feature = "rkyv", archive_attr(derive(Clone, Copy, PartialEq, Eq, Debug, Hash)))]
+#[cfg_attr(
+    any(feature = "rkyv_16", feature = "rkyv_32", feature = "rkyv_64"),
+    derive(Archive, Deserialize, Serialize)
+)]
+#[cfg_attr(
+    any(feature = "rkyv_16", feature = "rkyv_32", feature = "rkyv_64"),
+    archive_attr(derive(Clone, Copy, PartialEq, Eq, Debug, Hash))
+)]
 #[cfg_attr(feature = "arbitrary", derive(arbitrary::Arbitrary))]
 pub enum Weekday {
     /// Monday.