Our golf equipment segment continued to experience unprecedented demand, which combined with a strong performance by our supply chain team, delivered 29% revenue growth versus 2020, and 16% growth versus 2019.
Let's now turn to Page 6 and jump into our Q1 results by segment.
retail sales of golf equipment hard goods were up 49% compared to Q1 2019 and 72% compared to 2020, thus setting another record for Q1 just as the last two quarters delivered records for their respective time periods.
1 club brand in overall brand rating as well as the leader in innovation and technology.
Driving this performance, e-com was up 145% year over year in Q1, and company-owned stores comped up nearly 10% despite some code restrictions early in the quarter.
These investments enable our apparel business e-com to deliver 96% year-over-year growth in Q1.
And although the pandemic delayed our efforts, we still believe we'll be able to deliver $15 million of synergies in this segment over the coming years.
We now believe we will be either at the high end or modestly above our previous full year same venue sales expectations, which was 80 to 85%.
Globally, we have 66 company-owned venues in operation.
We successfully installed 1,533 bays in Q1, a new record despite the COVID challenges globally.
We now have just over 10,000 bays globally, which is significantly more than our largest competitor.
We remain on track for 8,000 bays this year.
We now expect that revenue and adjusted EBITDA for the full 12 months of 2021 will meet or beat 2019 results.
We are very pleased with our first-quarter results, with consolidated revenue increasing 47% and adjusted EBITDA increasing 113% compared to the same period in 2020.
Our consolidated revenue and adjusted EBITDA for the first quarter of 2021 increased by 26% and 38%, respectively compared to the first quarter of 2019.
As of March 31, 2021, our available liquidity, which is comprised of cash on-hand and availability under our credit facilities, was $713 million compared to $260 million at March 31, 2020.
Third, we recognized in the first quarter of 2021 a $253 million non-cash gain related to the write-off of our premerger Topgolf investment.
With those factors in mind, I will now provide some specific financial results for the first quarter of 2021 compared to the first quarter of 2020.
Today, we are reporting record consolidated first-quarter 2021 net revenues of $652 million, compared to $442 million for the same period in 2020, an increase of 210 million or 47%.
This increase was led by a 26% increase in the legacy Callaway business, as well as an incremental $93 million from the four weeks of the Topgolf business.
Changes in foreign currency rates had a $17 million favorable impact on first-quarter 2021 net sales.
We are also reporting for the first quarter of 2021 operating income of $76 million, an increase of $35 million or 85%, compared to $41 million for the same period in 2020.
On a non-GAAP basis, operating income for the first quarter of 2021 was $97 million, a 54 million or 126% increase compared to 43 million for the same period in 2020.
The increase in non-GAAP operating income was led by a $50 million increase in segment operating income from the legacy Callaway business as well as an incremental $4 million from the four weeks of the Topgolf business.
Other income was $244 million in the first quarter of 2021 compared to other expense of $3 million in the same period of the prior year.
This includes the $253 million non-cash gain related to the Topgolf merger.
On a non-GAAP basis, which includes Topgolf gain, other expense was $5 million in the first quarter of 2021 compared to other expense of $3 million for the comparable period in 2020.
The $2 million increase in other expense was primarily related to higher interest expense related to incremental interest from the convertible bonds issued in May 2020, plus four weeks of Topgolf interest, partially offset by a decrease in foreign currency-related losses.
Pretax income was $320 million in the first quarter of 2021 compared to $38 million for the same period in 2020.
Non-GAAP pre-tax income was $91 million in the first quarter of 2021 compared to non-GAAP pre-tax income of $41 million in the same period of 2020.
Earnings per share was $2.19 or approximately 125 million shares in the first quarter of 2021 compared to earnings of $0.30 or approximately 96 million shares in the first quarter of 2020.
Non-GAAP earnings per share was $0.62 in the first quarter of 2021 compared to earnings per share of $0.32 for the first quarter of 2020.
Fully diluted shares were 125 million in the first quarter of 2021 compared to 96 million shares for the same period in 2020.
The net 29 million share increase is primarily related to the issuance of additional shares in connection with the Topgolf merger.
Full year estimated diluted shares is approximately 176 million shares, which represents the weighted average shares issued in connection with the merger over approximately a 10-month period.
As of March 31, 2021, we had approximately 185 million shares that were issued and outstanding.
Adjusted EBITDA was $128 million in the first quarter of 2021 compared to $60 million in the first quarter of 2020 and $93 million in the first quarter of 2019.
Topgolf contributed adjusted EBITDA of $15 million for the four-week period.
To provide some additional perspective, The Topgolf first quarter 2021 EBITDA, the full three months was $17 million.
The golf equipment segment's net revenue increased $85 million or 29% to, $377 million in the first quarter of 2021, compared to $292 million in the first quarter of 2020.
Both golf club and golf ball sales increased by 26% and 50%, respectively.
The golf equipment segment operating income was $85 million or 22.5% of net revenues in the first quarter of 2021 compared to $59 million or 20.2% of net revenues in the first quarter of 2020, an increase of $26 million or 230 basis points.
The apparel, gear and other segment's net revenue increased $31 million or 21% to $182 million in the first quarter of 2021 compared to $151 million in the first quarter of 2020.
The increase was driven by a 23% increase in apparel sales as well as an 18% increase in gear and accessories and other.
The apparel, gear and other segment's operating income increased $24 million to $20 million compared to a loss of $4 million for the same period in the prior year.
In 2021, this equated to 11% of segment revenue, a 1,360-basis-point improvement over the first quarter of 2020.
The Topgolf segment net revenue was $93 million in the first quarter of 2021, which includes four weeks of the Topgolf business.
The Topgolf segment's operating income was $4 million for the four-week stub period.
To provide investors additional perspective, Topgolf's full first quarter net revenues were $236 million and full first quarter GAAP operating loss was $30 million and on a non-GAAP basis, Topgolf's operating loss was 15 million.
As of March 31, 2021, available liquidity was $713 million compared to $260 million at the end of the first quarter.
At March 31, 2020, we had total net debt of $1,160 million, including 640 million of Topgolf related net debt.
The Topgolf debt includes landlord financing of $222 million related to financing the venues business.
Our consolidated net accounts receivable was $329 million, an increase of 27% compared to $260 million at the end of the first quarter of 2020.
Days sales outstanding decreased slightly to 61 days on March 31, 2021, compared to 62 days as of March 31, 2020.
The increase in net accounts receivable primarily is attributable to the increase in first quarter revenue, but also includes an incremental $9 million of accounts receivable.
Also, this on Slide 13, our inventory balance decreased by 19% to $336 million at the end of the first quarter of 2021 compared to 413 million at the end of the first quarter of the prior year.
The $77 million decrease was due to the high demand we are experiencing in the golf equipment business, recovery of our soft goods businesses, as well as inventory reduction efforts in the soft goods business.
Capital expenditures for the first quarter of 2021 were $29 million.
This includes $16 million related to Topgolf.
From a full-year 2021 forecast perspective, the legacy Callaway forecast is increasing to approximately $65 million versus the previous forecast of 50 million due to capacity investments in our plants and warehouses, as well as increasing the number of play in TravisMathew retail stores.
The full year and 12-month forecast for Callaway and Topgolf is approximately $265 million, driven primarily by the new venue openings.
If you include Topgolf for only 10 months, that would be approximately $235 million.
Depreciation and amortization expense was $20 million in the first quarter of 2021.
Non-GAAP depreciation and amortization expense was $17 million in the first quarter of 2021 compared to $8 million in 2020.
This includes $9 million of non-GAAP depreciation and amortization related to Topgolf.
To help give investors additional perspective, the Topgolf full Q1 non-GAAP depreciation and amortization was $27 million.
For the full year of 2021, we expect non-GAAP depreciation and amortization expense to be approximately $155 million, which includes 115 million for the Topgolf business.
We are not providing specific revenue and earnings guidance ranges for 2021 at this time due to the continued uncertainty surrounding the duration and impact of COVID-19.
This negatively impacted gross margins for the golf equipment business in the first quarter of 2021 by approximately 85 basis points and will continue to affect comparisons with prior periods for the balance of the year as prior periods were not changed.
We previously estimated that the freight container shortage was expected to have a negative impact of $13 million on freight costs in 2021, with a substantial majority affecting the first half.
At this point, the impact of COVID-19 in our overall freight cost is expected to be greater than the 13 million, with more costs hitting the balance of the year than originally expected.
We also previously estimated that operating expenses for the legacy Callaway business would be approximately $78 million higher than in 2019 due to the negative impact of foreign currency inflationary pressures and continued investment in the company's business, which included investment needed to assume the apparel business, investment in the other soft goods businesses and investment in Pro Tour.
Given the faster-than-expected recovery of both businesses, and with all three of our operating segments performing above plan in the first quarter, we now project that revenue and adjusted EBITDA from our legacy businesses will exceed 2019 levels, and then our Topgolf business for the full 12 months of 2021 will meet or exceed 2019 levels, which is a year faster than expected.
As a reminder, in 2019, the Calllaway legacy business reported revenue of $1.7 billion and adjusted EBITDA of $211 million.
For full year 2019, that's 12 months.
The Topgolf business reported revenue of $1.06 billion and adjusted EBITDA of $59 million in 2019.
Please note that Callaway's actual reported full year financial results will only include 10 months of Topgolf results in 2021, and therefore, will not include January and February results which were in the aggregate, $143 million in revenue and $2.3 million in adjusted EBITDA.

Summary:
With those factors in mind, I will now provide some specific financial results for the first quarter of 2021 compared to the first quarter of 2020.
Earnings per share was $2.19 or approximately 125 million shares in the first quarter of 2021 compared to earnings of $0.30 or approximately 96 million shares in the first quarter of 2020.
Non-GAAP earnings per share was $0.62 in the first quarter of 2021 compared to earnings per share of $0.32 for the first quarter of 2020.
We are not providing specific revenue and earnings guidance ranges for 2021 at this time due to the continued uncertainty surrounding the duration and impact of COVID-19.