diff --git a/src/naive/date.rs b/src/naive/date.rs
index c4daae13..4b965d27 100644
--- a/src/naive/date.rs
+++ b/src/naive/date.rs
@@ -1688,7 +1688,7 @@ impl Datelike for NaiveDate {
 
     #[inline]
     fn iso_week(&self) -> IsoWeek {
-        IsoWeek::from_yof(self.year(), self.of())
+        IsoWeek::from_yof(self.year(), self.ordinal(), self.of().flags())
     }
 
     /// Makes a new `NaiveDate` with the year number changed, while keeping the same month and day.
@@ -2516,7 +2516,7 @@ mod serde {
 #[cfg(test)]
 mod tests {
     use super::{Days, Months, NaiveDate, MAX_YEAR, MIN_YEAR};
-    use crate::naive::internals::YearFlags;
+    use crate::naive::internals::{YearFlags, A, AG, B, BA, C, CB, D, DC, E, ED, F, FE, G, GF};
     use crate::{Datelike, TimeDelta, Weekday};
 
     // as it is hard to verify year flags in `NaiveDate::MIN` and `NaiveDate::MAX`,
@@ -3375,6 +3375,36 @@ mod tests {
         }
     }
 
+    #[test]
+    fn test_isoweekdate_with_yearflags() {
+        for (year, year_flags, _) in YEAR_FLAGS {
+            // January 4 should be in the first week
+            let jan4 = NaiveDate::from_ymd_opt(year, 1, 4).unwrap();
+            let iso_week = jan4.iso_week();
+            assert_eq!(jan4.of().flags(), year_flags);
+            assert_eq!(iso_week.week(), 1);
+        }
+    }
+
+    // Used for testing some methods with all combinations of `YearFlags`.
+    // (year, flags, first weekday of year)
+    const YEAR_FLAGS: [(i32, YearFlags, Weekday); 14] = [
+        (2006, A, Weekday::Sun),
+        (2005, B, Weekday::Sat),
+        (2010, C, Weekday::Fri),
+        (2009, D, Weekday::Thu),
+        (2003, E, Weekday::Wed),
+        (2002, F, Weekday::Tue),
+        (2001, G, Weekday::Mon),
+        (2012, AG, Weekday::Sun),
+        (2000, BA, Weekday::Sat),
+        (2016, CB, Weekday::Fri),
+        (2004, DC, Weekday::Thu),
+        (2020, ED, Weekday::Wed),
+        (2008, FE, Weekday::Tue),
+        (2024, GF, Weekday::Mon),
+    ];
+
     #[test]
     #[cfg(feature = "rkyv-validation")]
     fn test_rkyv_validation() {
diff --git a/src/naive/internals.rs b/src/naive/internals.rs
index 0af7d449..451d9372 100644
--- a/src/naive/internals.rs
+++ b/src/naive/internals.rs
@@ -322,14 +322,6 @@ impl Of {
         weekday_from_u32_mod7((of >> 4) + (of & 0b111))
     }
 
-    #[inline]
-    pub(super) fn isoweekdate_raw(&self) -> (u32, Weekday) {
-        // week ordinal = ordinal + delta
-        let Of(of) = *self;
-        let weekord = (of >> 4).wrapping_add(self.flags().isoweek_delta());
-        (weekord / 7, weekday_from_u32_mod7(weekord))
-    }
-
     #[cfg_attr(feature = "cargo-clippy", allow(clippy::wrong_self_convention))]
     #[inline]
     pub(super) const fn to_mdf(&self) -> Mdf {
@@ -740,15 +732,6 @@ mod tests {
         }
     }
 
-    #[test]
-    fn test_of_isoweekdate_raw() {
-        for &flags in FLAGS.iter() {
-            // January 4 should be in the first week
-            let (week, _) = Of::new(4 /* January 4 */, flags).unwrap().isoweekdate_raw();
-            assert_eq!(week, 1);
-        }
-    }
-
     #[test]
     fn test_of_to_mdf() {
         for i in 0u32..=8192 {
diff --git a/src/naive/isoweek.rs b/src/naive/isoweek.rs
index 45a142a0..1d0ddfba 100644
--- a/src/naive/isoweek.rs
+++ b/src/naive/isoweek.rs
@@ -5,7 +5,7 @@
 
 use core::fmt;
 
-use super::internals::{Of, YearFlags};
+use super::internals::YearFlags;
 
 #[cfg(any(feature = "rkyv", feature = "rkyv-16", feature = "rkyv-32", feature = "rkyv-64"))]
 use rkyv::{Archive, Deserialize, Serialize};
@@ -38,14 +38,14 @@ impl IsoWeek {
     // because the year range for the week date and the calendar date do not match and
     // it is confusing to have a date that is out of range in one and not in another.
     // currently we sidestep this issue by making `IsoWeek` fully dependent of `Datelike`.
-    pub(super) fn from_yof(year: i32, of: Of) -> Self {
-        let (rawweek, _) = of.isoweekdate_raw();
+    pub(super) fn from_yof(year: i32, ordinal: u32, year_flags: YearFlags) -> Self {
+        let rawweek = (ordinal + year_flags.isoweek_delta()) / 7;
         let (year, week) = if rawweek < 1 {
             // previous year
             let prevlastweek = YearFlags::from_year(year - 1).nisoweeks();
             (year - 1, prevlastweek)
         } else {
-            let lastweek = of.flags().nisoweeks();
+            let lastweek = year_flags.nisoweeks();
             if rawweek > lastweek {
                 // next year
                 (year + 1, 1)